Influence of Platform Switching, Abutment Design and Connection Protocols on the Stability of Peri-Implant Tissues. A Systematic Review

PURPOSE

To appraise the effect of abutment factors namely platform switching, design and connection protocols on the stability of peri-implant tissues.

MATERIALS AND METHODS

An electronic and hand search were conducted. Randomized control trials and controlled prospective studies of at least one-year follow-up, published in the last 12 years, were included.

RESULTS

Initial electronic database search generated 3054 studies, while individual journal and hand searching resulted in 232 articles. Sixty-three publications were selected for full text analysis based on inclusion and exclusion criteria. Nineteen articles investigated platform switching. Fourteen studies reported positive influence of platform switching while five studies did not find a significant difference in bone loss compared to platform matched abutments. Two articles reported on concave abutments and found no advantage over conventional abutments. Seven studies investigated "one-abutment-one-time protocol", two found comparable results to multiple abutment disconnections while five studies suggested better soft and hard tissue maintenance. The risk of bias was unclear or high in most studies.

CONCLUSION

Platform switched abutments may reduce crestal bone loss during the first year. There is insufficient evidence to suggest better clinical outcomes of concave abutment. There is insufficient evidence to indicate the superiority of 'one abutment-one-time protocol'.

Influence of Platform Switching, Abutment Design and Connection Protocols on the Stability of Peri-Implant Tissues. A Systematic Review

PURPOSE

To appraise the effect of abutment factors namely platform switching, design and connection protocols on the stability of peri-implant tissues.

MATERIALS AND METHODS

An electronic and hand search were conducted. Randomized control trials and controlled prospective studies of at least one-year follow-up, published in the last 12 years, were included.

RESULTS

Initial electronic database search generated 3054 studies, while individual journal and hand searching resulted in 232 articles. Sixty-three publications were selected for full text analysis based on inclusion and exclusion criteria. Nineteen articles investigated platform switching. Fourteen studies reported positive influence of platform switching while five studies did not find a significant difference in bone loss compared to platform matched abutments. Two articles reported on concave abutments and found no advantage over conventional abutments. Seven studies investigated "one-abutment-one-time protocol", two found comparable results to multiple abutment disconnections while five studies suggested better soft and hard tissue maintenance. The risk of bias was unclear or high in most studies.

CONCLUSION

Platform switched abutments may reduce crestal bone loss during the first year. There is insufficient evidence to suggest better clinical outcomes of concave abutment. There is insufficient evidence to indicate the superiority of 'one abutment-one-time protocol'.

Effects of transforming growth factor-β1 on plasminogen activation in stem cells from the apical papilla: role of activating receptor-like kinase 5/Smad2 and mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signalling

AIM

To study the effects of TGF-β1 on the plasminogen activation (PA) system of stem cells from the apical papilla (SCAP) and its signalling.

METHODOLOGY

SCAP cells were isolated from the apical papilla of immature permanent teeth extracted for orthodontic reasons. They were exposed to various concentration of TGF-β1 with/without pretreatment and coincubation by SB431542 (ALK/Smad2/3 inhibitor), or U0126 (MEK/ERK inhibitor). MTT assay, Western blotting and enzyme-linked immunosorbent assay (ELISA) were used to detect their effects on cell viability, and the protein expression of plasminogen activator inhibitor-1 (PAI-1), urokinase-type plasminogen activator (uPA), uPA receptor (uPAR) and their secretion. The paired Student's t-test was used for statistical analysis.

RESULTS

TGF-β1 significantly stimulated PAI-1 and soluble uPAR (suPAR) secretion of SCAP cells (P < 0.05), whereas uPA secretion was inhibited. Accordingly, TGF-β1 induced both PAI-1 and uPAR protein expression of SCAP cells. SB431542 (an ALK5/Smad2/3 inhibitor) pretreatment and coincubation prevented the TGF-β1-induced PAI-1 and uPAR of SCAP. U0126 attenuated the TGF-β1-induced expression/secretion of uPAR, but not PAI-1 in SCAP. SB431542 reversed the TGF-β1-induced decline of uPA.

CONCLUSIONS

TGF-β1 may affect the repair/regeneration activities of SCAP via differential increase or decrease of PAI-1, uPA and uPAR. These effects induced by TGF-β1 are associated with ALK5/Smad2/3 and MEK/ERK activation. Elucidation the signalling pathways and effects of TGF-β1 is useful for treatment of immature teeth with open apex by revascularization/revitalization procedures and tissue repair/regeneration.

Abstract P1-16-03: Phase II randomized clinical trial (RCT) of metformin (MET) vs placebo (PLAC) in combination with chemotherapy (CXT) in refractory locally advanced (LABC) or metastatic breast cancer (MBC)

Background: MET treatment of diabetes is associated with improved BC outcomes. Hirsch et al (Cancer Res 2009;69:7505-7511) suggested MET may act synergistically with CXT in BC rodent models. We conducted a double-blind Phase II RCT of CXT plus MET vs placebo in LABC/MBC.

Methods: Non-diabetic BC patients (pts) about to commence 1st-4th line CXT (prespecified anthracycline, taxane, vinorelbine, platinum or capecitabine; HER2 Rx permitted) for MBC or refractory LABC (any ER, PgR, HER2) were eligible if (i) age 18-75, (ii) ECOG 0-2, (iii) adequate hepatic, renal, bone marrow, cardiac function and (iv) measurable or evaluable disease. Those with CNS metastases, recent MET use or radiotherapy to target lesions, intake of ≥ 3 alcoholic drinks/day, history of lactic acidosis or current/planned pregnancy or lactation were ineligible. Randomization was to MET 850 mg po bid (or identical PLAC bid) with a 2 day ramp up of one tablet/day; dose was reduced/drug discontinued in a pre-specified manner for grade 2-4 toxicity. Disease status and toxicity/HRQOL were assessed at baseline and q9 weeks until progression. Primary outcome was progression-free survival (PFS); secondary outcomes included survival (OS), response and toxicity. With 40 subjects and type one error 0.2 (1-sided), a PFS HR of 0.58 could be detected with 80% power. PFS was analyzed using Cox proportional hazards regression.

Results: 40 pts were randomized (22 MET, 18 PLAC). Mean age 55.4 vs 56.9 years; ER/PgR+ in 86.4 vs 83.3%; time from 1st metastases to randomization 297 vs 405 days, in MET vs PLAC respectively. MET pts were more likely to have visceral metastases (95.5% vs 72.2% PLAC) and less likely to be HER2+ (9.1% vs 23.5% PLAC). CXT was 1st line in 68.2% MET and 66.7% PLAC pts. Toxicity - # events: Gr 4: 0 MET vs 1 PLAC, Gr 3: 14 MET vs 14 PLAC; Gr 1 or 2: 193 MET (mainly GI) vs 53 PLAC. Best response: PR 18.2% MET vs 22.2% PLAC, SD 31.8% MET vs 11.1% PLAC, PD 45.4% MET vs 50.0% PLAC, P = 0.41. Mean PFS 164 days MET vs 192 days PLAC; HR (MET vs PLAC) 1.14 (95% CI 0.59-2.2), 1-sided p=0.65. Mean OS 645 MET vs 831 PLAC days; HR (MET vs PLAC) 1.6, 95% CI 0.72-3.54, 1-sided p=0.88.

Conclusion: In these BC pts receiving 1st-4th line CXT, MET (vs PLAC) did not improve response rates, PFS or OS. Gr 1 and 2 toxicity was higher with MET than PLAC. These results do not support use of MET with CXT in refractory LABC/MET BC. MA32, an adjuvant trial of MET vs PLAC in early BC will provide information on MET in the adjuvant setting.

Funded by the Breast Cancer Research Foundation (New York) and Hold'em for Life Charity (Toronto)

Citation Format: Goodwin PJ, Ennis M, Cescon DW, Elser C, Haq R, Hamm CM, Lohmann AE, Pimentel I, Chang MC, Dowling RJ, Stambolic V. Phase II randomized clinical trial (RCT) of metformin (MET) vs placebo (PLAC) in combination with chemotherapy (CXT) in refractory locally advanced (LABC) or metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-16-03.

Abstract P4-02-01: Analytical validation of an automated digital scoring protocol for Ki67: International multicenter collaboration study

Background/Goal: Ki67 expression has been a valuable prognostic marker in breast cancer, but has not seen broad adoption due to lack of standardization between institutions. Automation could represent a solution. Here we tested 3 automated digital image analysis (DIA) platforms including an open source platform to: (i) Investigate the reproducibility of Ki67 measurement across platforms with supervised classifiers performed by the same operator and by multiple operators. (ii) Compare accuracy of the 3 DIA platforms against outcome (prognostic potential). (iii) Assess inter-laboratory reproducibility of a calibrated DIA tool to evaluate Ki67 in breast cancer among 10 participating labs of the International Ki67 in Breast Cancer Working Group (IKWG).

Methods: The Mib-1 antibody (Dako) was used to detect Ki67 (dilution 1:100). HALO (H) (IndicaLabs), QuantCenter (QC) (3DHistech), QuPath (QP) (open-source software) digital image analysis (DIA) platforms were used to evaluate Ki67 expression. As a ground truth, we evaluated Ki67 LI with meticulous manual tissue segmentation using the Spectrum Webscope (SW) (Aperio). Calibration was performed using 30 ER+ breast cancer cases from phase 3 of the IKWG initiative where blocks were centrally cut and stained for Ki67. The inter-laboratory analysis was done with 10 participating laboratories divided into 2 groups where members within the same group were given the same set of images. The outcome cohort consisted of 149 breast cancer cases from the Yale Pathology archives in tissue microarray format. Intra-class correlation coefficient (ICC) was used to measure reproducibility with the pre-specified criterion for success being to exceed 0.80. Kaplan-Meier analysis supported with log-rank test was performed to assess prognostic potential.

Results: All 3 DIA platforms showed excellent inter-platform reproducibility (ICC: 0.933, CI: 0.879-0.966). Also, excellent reproducibility was found between all DIA platforms and the reference standard Ki67 values of SW (QP ICC: 0.970, CI: 0.936-0.986; H ICC: 0.968, CI: 0.933-0.985; QC ICC: 0.964, CI: 0.919-0.983). The intra-DIA reproducibility was also excellent for all platforms (QP ICC: 0.992, CI: 0.986-0.996; H ICC: 0.972, CI: 0.924-0.988; QC ICC: 0.978, CI: 0.932-0.991). Comparing each DIA against outcome, the hazard ratios were similar (QP=3.309, H=3.077, QC=3.731). The inter-operator reproducibility was particularly high (ICC: 0.962-0.995). As QP is open source software and also showed the lowest intra-DIA platform variability, we selected the QP platform to investigate inter-laboratory reproducibility among 10 IKWG labs. The different-section ICC across the 10 labs was 0.974 (CI: 0.954 - 0.986). The same-section ICC estimate was 0.984 (CI: 0.971-0.992) for group 1 and 0.978 (CI: 0.956-0.989) for group 2.

Conclusions: Our results showed outstanding reproducibility both within and between DIA platforms. We also found the platforms essentially indistinguishable with respect to prediction of breast cancer patient outcome. Automated Ki67 evaluation using a calibrated, open-source DIA platform (QuPath) met the pre-specified criterion of success in the multi-institutional setting. Assessment of clinical utility is planned.

Citation Format: Acs B, Leung SC, Pelekanou V, Bai Y, Martinez-Morilla S, Toki M, Chang MC, Gholap A, Jadhav A, Hugh JC, Bigras G, Laurinavicius A, Augulis R, Levenson R, Todd A, Piper T, Virk S, van der Vegt B, Hayes DF, Dowsett M, Nielsen TO, Rimm DL. Analytical validation of an automated digital scoring protocol for Ki67: International multicenter collaboration study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-02-01.

Abstract P4-15-05: The presence of one or multiple foci of microinvasion is not associated with an increased risk of local recurrence in women with ductal carcinoma in situ treated with breast conserving therapy

Background: Ductal Carcinoma in Situ (DCIS) is a non-invasive breast cancer often treated with breast-conserving surgery (BCS) with or without radiotherapy (RT). It is unclear if the presence of microinvasion (MI) (invasion ≤1mm) is associated with an increased risk of LR (DCIS or invasive) or invasive LR compared to women with pure DCIS. In addition, the impact of multiple foci (&gt;2) of MI compared to pure DCIS is also unknown; therefore, it is unclear if some women with MI require more aggressive treatment. We evaluated the impact of the presence of MI and the number of foci of MI on the risks of any LR and invasive LR in a population of women with DCIS with and without MI treated with BCS.

Methods: The cohort includes all women diagnosed with pure DCIS or DCIS with MI in Ontario from 1994-2003 treated with BCS +/- RT. All cases had systematic pathology review to confirm the presence and number of foci of MI. Treatment and outcomes were ascertained through administrative databases and validated by chart review. Cox proportional hazards model was used to evaluate the impact of MI and the number of foci of MI (1 vs &gt;2 foci) on the development of any LR and invasive LR compared to cases with pure DCIS. The 10-yr local recurrence-free survival (LRFS) and invasive LRFS rates were calculated using the Kaplan-Meier approach with differences compared using the log-rank test.

Results: The population cohort includes 2,988 women with DCIS treated by BCS (N=2,721 pure DCIS, N= 267 DCIS with MI). Median follow-up (12 years; p=.23) and median age at diagnosis (58 years; p=.17) were similar in both groups. RT was given in 58% of cases with MI and 51% of cases with pure DCIS (p=.03). Hormonal therapy was utilized in 7.1% of women with MI and 5.3% of women with pure DCIS (p=.22). LR developed in 59 (22.1%) cases with MI and 530 (19.6%) cases of pure DCIS. Women with MI were more likely to have high nuclear grade (p&lt;.001), and larger tumor size (p&lt;.001) compared to those without MI. On multivariable analyses adjusted for age, the presence of 1 focus of MI(HR=.92, 95% CI: .64-1.33) or ≥2 foci of MI (HR=1.26, 95% CI: .85-1.85) was not associated with an increased risk of any LR compared to cases with pure DCIS. Factors associated with any LR were age &lt;50 years at diagnosis, RT, multifocality and high nuclear grade. The presence of 1 focus of MI (HR=.86, 95% CI: .52-1.40) or &gt; 2 foci of MI (HR=1.45, 95% CI: .90-2.32) was also not associated with an increased risk of invasive LR compared to cases of pure DCIS. Among women treated with BCS alone, the 10 year LRFS rates were 80%, 75% and 73% for women with pure DCIS, 1 focus, &gt;2 foci of MI (p=.10). The invasive LRFS rates were 89%, 91% and 85% (p=.26). Among women treated with BCS+RT, the 10 year LRFS rates were 87%, 88% and 80% (p=0.32) for women with pure DCIS, 1 focus or ≥2 foci of MI. The invasive LRFS rates were 93%, 90% and 86% (p=.44). There was no interaction between the presence of MI and RT.

Conclusions: Women with DCIS with one or multiple foci of microinvasion (&lt;1mm) treated by breast conserving therapy do not have an increased risk of LR or invasive LR compared to women with pure DCIS.

Citation Format: Lalani N, Paszat L, Sutradhar R, Gu S, Fong C, Nofech-Mozes S, Hanna W, Tuck A, Youngson B, Miller N, Done SJ, Chang MC, Sengupta S, Elavathil L, Jani PA, Bonin M, Rakovitch E. The presence of one or multiple foci of microinvasion is not associated with an increased risk of local recurrence in women with ductal carcinoma in situ treated with breast conserving therapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-15-05.

Abstract P2-03-01: Analytical validation of a standardized scoring protocol for Ki67 assessed on breast excision whole sections: An international multicenter collaboration

Aims: (i) Determine whether between-observer reproducibility for Ki67 when assessed on whole sections according to a standardized scoring protocol is adequate for clinical application. (ii) Compare between-observer reproducibility of Ki67 scores assessed on hot-spots to scores using a global method that averages across a tissue section.

Background: The nuclear proliferation biomarker Ki67 has multiple potential roles in breast cancer, including aiding decisions based on prognosis, but unacceptable levels of between-laboratory variability have been observed. The International Ki67 in Breast Cancer Working Group has undertaken a systematic program to determine whether Ki67 measurement can be analytically validated and standardized across labs. In phase 1, variability in visual interpretation was identified as an important source of variability. Phases 2 and 3a showed that adherence to defined scoring methods substantially improved reproducibility in scoring tissue microarrays and core-cut biopsies. We now assess whether acceptable reproducibility can be achieved on whole sections.

Methods: Adjacent sections from 30 primary ER+ breast cancers were centrally stained for Ki67 to assemble 4 sets of 30 stained tumor sections, circulated around 23 labs in 12 countries. Ki67 was scored by 2 methods by all labs: (a) global: 4 fields of 100 tumor cells each were selected to reflect observed heterogeneity in nuclear staining (b) hot-spot: the field with highest Ki67 percentage of tumor cells with nuclear staining was selected and up to 500 cells scored. Ki67 scores were log2-transformed for statistical analyses and back-transformed for presentation. The primary objective was to assess whether either method could achieve an intraclass correlation coefficient (ICC) significantly greater than 0.8, considered substantial to almost-perfect reproducibility. Secondary objectives were to assess which method had highest observed ICC and to assess whether observers identified the same “hot-spots”.

Results: ICC for the global method was 0.87 (95%CI: 0.799-0.93), marginally meeting the prespecified success criterion. The ICC for the hot-spot method was 0.83 (95%CI: 0.74-0.90) and had a CI extending below the success criterion. Across the 23 labs, geometric mean value of the 30 scores ranged from 8.5 to 19.6 for the global method and from 12.8 to 30.3 for the hot-spot method. The overall mean (95% CI) of these values was 12.9 (11.9-14.0) and 20.9 (19.1-22.8), respectively. Visually, between-laboratory agreement in location of selected hot-spot varies between cases. The median times for scoring were 9 and 6 minutes for global and hot-spot methods respectively.

Conclusions: The global method marginally met the prespecified criterion of success; it should now be evaluated for clinical validity in appropriate cohorts of cases. The hot-spot method was observed to have slightly less reproducibility between labs. The time taken for scoring by either method is practical using counting software we are making publicly available. Establishment of external quality assessment schemes is likely to improve the reproducibility between labs further.

(Supported by a grant from the Breast Cancer Research Foundation)

Citation Format: Nielsen TO, Leung SCY, Zabaglo LA, Arun I, Badve SS, Bane AL, Bartlet JMS, Borgquist S, Chang MC, Dodson A, Ehinger A, Fineberg S, Focke CM, Gao D, Gown AM, Gutierrez C, Hugh JC, Kos Z, Lænkholm A-V, Mastropasqua MG, Moriya T, Nofech-Mozes S, Osborne CK, Penault-Llorca FM, Piper T, Sakatani T, Salgado R, Starczynski J, Sugie T, van der Vegt B, Viale G, Hayes DF, McShane LM, Dowsett M. Analytical validation of a standardized scoring protocol for Ki67 assessed on breast excision whole sections: An international multicenter collaboration [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-01.

Abstract P2-12-02: Is breast-conserving therapy effective in women with large ductal carcinoma in situ (DCIS) lesions? A population-based analysis

Background: Most women diagnosed with DCIS will be treated by breast-conserving surgery (BCS) with or without radiotherapy (RT). Data on outcomes following breast-conserving therapy are predominantly based on women with small (&lt;25mm) lesions. The paucity of data on outcomes of women with larger (&gt;40mm) DCIS lesions leads to uncertainty of the appropriateness of breast-conserving therapy for women with larger lesions. Specifically, it is unclear if women with large tumors experience higher risks of local recurrence (LR) and invasive LR after BCS+/-RT that would preclude recommendations of breast-conserving therapy. We report the outcomes and evaluate the impact of large tumor size (&gt;40mm) on recurrence risk in a population of women with pure DCIS treated by BCS alone or with RT.

Methods: The cohort includes all women diagnosed with DCIS in Ontario from 1994-2003 treated with BCS +/- RT; 82% had pathology review. Treatment and outcomes were ascertained through administrative databases and validated by chart review. Cox proportional hazards model was used to evaluate the impact of tumor size (≤10mm,11-25mm, 26-39mm, ≥40mm) on the development of any LR (DCIS or invasive) and invasive LR. The 10 and 15-year LR-free survival (LRFS) and invasive LRFS rates were calculated using the Kaplan-Meier method with differences compared using the log-rank test.

Results: The cohort includes 3262 women with DCIS treated by BCS (N=1635 had RT). Median age at diagnosis was 59 years (IQR 50-68 years). Median follow-up was 13 years (IQR 8-15 years). Distribution of tumor size: 707 (22%) ≤10mm, 524 (16%) 11-25mm, 107 (3%) 26-39mm, 84 (3%) ≥40mm, unable to determine in 1840 (56%). Women with lesions ≥ 40mm were more likely to be ≤50 years of age at diagnosis (p=.02), have high nuclear grade (p&lt;.001), multifocality (p&lt;.001), and positive margins (p&lt;.001) compared to women with smaller lesions. On multivariable analyses adjusted for age and year of diagnosis, tumor size ≥40mm was significantly associated with an increased risk of LR compared to size ≤10mm (HR=2.5, 95%CI:1.64-3.81). Other factors associated with LR were age &lt;50 years (p&lt;.001), omission of RT (p&lt;.001), high nuclear grade (p=.002), and multifocality (p=.0008). Tumor size ≥40mm was not significantly associated with an increased risk of invasive LR (HR=1.68, 95%CI:.94-3.04). Women with tumour size ≥40mm treated with BCS alone had lower 10 and 15 year LRFS (53% and 41%) and invasive LRFS rates (78% and 75%) compared to women with smaller lesions. However, women with larger lesions treated with RT had significantly higher LRFS and invasive LRFS rates

Outcomes by tumour size for women with DCIS treated with BCS with or without RT  ≤10mm N=70711-25mm N=52426-39mm N=107≥40mm N=84p-valueBCS AloneLRFS (%)      10 yr85797053&lt;0.001 15 yr81746741  Invasive LRFS (%)      10 yr928786780.03 15 yr89838375 BCS + RTLRFS (%)      10 yr928874850.01 15 yr86847079  Invasive LRFS (%)      10 yr959492910.27 15 yr90918789 

. There was a significant interaction between tumor size ≥40mm and RT (p=.02).

Conclusions: Women with DCIS lesions ≥40mm treated by BCS alone experience significantly higher risks of LR and invasive LR compared to smaller lesions but this risk can be mitigated with the addition of RT.

Citation Format: Lalani N, Paszat L, Nofech-Mozes S, Sutradhar R, Gu S, Hanna W, Fong C, Miller N, Youngson B, Done SJ, Tuck A, Chang MC, Sengupta S, Jani PA, Bonin M, Rakovitch E. Is breast-conserving therapy effective in women with large ductal carcinoma in situ (DCIS) lesions? A population-based analysis [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-12-02.

Clinical utility of multigene profiling assays in early-stage breast cancer

BACKGROUND

This clinical practice guideline was developed to determine the level of evidence supporting the clinical utility of commercially available multigene profiling assays and to provide guidance about whether certain breast cancer patient populations in Ontario would benefit from alternative tests in addition to Oncotype dx (Genomic Health, Redwood City, CA, U.S.A.).

METHODS

A systematic electronic Ovid search of the medline and embase databases sought out systematic reviews and primary literature. A systematic review and practice guideline was written by a working group and was then reviewed and approved by Cancer Care Ontario's Molecular Oncology Advisory Committee.

RESULTS

Twenty-four studies assessing the clinical utility of Oncotype dx, Prosigna (NanoString Technologies, Seattle, WA, U.S.A.), EndoPredict (Myriad Genetics, Salt Lake City, U.S.A.), and MammaPrint (Agendia, Irvine, CA, U.S.A.) were included in the evidence base.

CONCLUSIONS

The clinical utility of multigene profiling assays is currently established for an appropriate subset of patients with estrogen receptor-positive, her2-negative, node-negative breast cancer for whom a decision to give chemotherapy is difficult to make. For patients with estrogen receptor-positive tumours who receive tamoxifen alone, Oncotype dx, Prosigna, and EndoPredict validly identify a low-risk population with favourable outcomes, indicating that a low-risk assay result is actionable and the decision to withhold chemotherapy is supported. Clinical evidence indicates that a high Oncotype dx recurrence score can predict for chemotherapy benefit, but a high Prosigna or EndoPredict score, although prognostic, is not, based on clinical trial evidence, directly actionable. Prosigna and EndoPredict are statistically more likely to identify a population at risk for recurrence beyond 5 years, but that information is currently not actionable because of a lack of interventional studies.

Abstract P6-02-03: Leptin receptor (OB-R) in breast carcinoma tissue: Ubiquitous expression and correlation with leptin-mediated signaling, but not with systemic markers of obesity

Background/Aims: Obesity is associated with a 30-50% increased risk of breast-cancer (BC) mortality, most consistently in estrogen receptor (ER) positive disease, through unclear mechanisms. Leptin is a multi-functional protein with key actions on adipose tissue. In pre-clinical studies, leptin stimulates the growth, survival, and progression of BC cells through both estrogen dependent and other (e.g. JAK/STAT, PI3K/Akt, MAPK) pathways. Leptin has also been associated with increased BC risk and poor prognosis. Our aim was to correlate tumor leptin-receptor (OB-R) expression with tissue markers of cell signaling and systemic markers of obesity, inflammation, and metabolism in a cohort of ER+/HER2- BC patients.

Methods: From our biorepository, we identified ER+/HER2- BC patients having both blood and tissue samples available. Data included BMI, menopausal status, and family/cancer/medical history, tumor histology, grade, stage, and ER/PgR/HER2 status. We performed blood assays for factors related to inflammation, tumor growth, hormonal regulation, and metabolism (see below). Immunohistochemistry for OB-R, pAkt (S473), pERK (T202/Y204), and insulin-receptor (IR) was performed on archived tissue, and scored for % positive cells and intensity of staining. Allred and H-scores were calculated. Associations with OB-R scores were calculated using Pearson, Spearman, and χ2 methods.

Results: 129 patients were eligible; 69.8% were post-menopausal and mean BMI was 27.8 ± 6.5 kg/m2. Most tumors were no-special-type (79%), PgR+ (90%), and node-neg (78%). The tissue expression of OB-R and other markers was scorable in 118 (91%) cases.

OB-R was expressed in all 118/118 cancers (Allred score range: 3 to 8; median 7, mean 6.61). High blood leptin did not downregulate OB-R (Spearman R=0), even though leptin was strongly correlated with BMI (Pearson r=0.78, p&lt;0.00001). Increasing OB-R correlated with phosphorylation of Akt (R=0.19) but not ERK (R=0.08). By contrast, high BMI was associated with lower Akt (R=-0.18) and ERK (R=-0.11) phosphorylation.

OB-R correlated with ER (Spearman R = 0.27), PgR (R=0.29), and insulin receptor (R = 0.24), weakly correlated with estradiol (Spearman, R=0.11) and fasting glucose (R=0.18), and negatively correlated with systemic IL-2 (R=-0.11) and IL-6 (R=-0.21). OB-R was not correlated with other blood markers (insulin, HOMA, PAI-1, IL-1ẞ, IL-8, VEGF, EGF, TNF-α,hsCRP, SHBG, or estrogens) or tumor grade.

Conclusions: OB-R is highly expressed in breast tumor tissue even in non-obese patients. Although leptin and BMI did not modulate OB-R expression, downstream signaling (e.g. Akt, ERK) did show a BMI-dependent effect, albeit of limited magnitude. This suggests that leptin acts on breast cancer cells through OB-R activation and downstream Akt/ERK signaling, without a coupled change in total OB-R expression. Further work is needed to elucidate the roles of inflammation, estrogens, and regulatory mechanisms within the PI3K-PTEN and Ras-MAPK cell-signaling networks.

The authors wish to acknowledge the generous support of the Breast Cancer Research Foundation and Hold'Em For Life Charity Challenge.

Citation Format: Chang MC, Ennis M, Dowling RJO, Stambolic V, Goodwin PJ. Leptin receptor (OB-R) in breast carcinoma tissue: Ubiquitous expression and correlation with leptin-mediated signaling, but not with systemic markers of obesity [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-02-03.

Abstract P1-02-03: Circulating inflammatory markers, growth factors, and tumor associated antigens in women with early stage breast cancer receiving neoadjuvant metformin

Background: Numerous clinical studies have reported that diabetic patients receiving metformin exhibit decreased cancer incidence and cancer related mortality. Metformin's mechanism of anti-tumor action has been attributed to both direct effects on cancer cells and systemic changes in insulin metabolism. Indeed, metformin reduces circulating insulin levels, which may be integral to its effectiveness in the breast cancer (BC) setting where hyperinsulinemia is associated with both recurrence and death. While the impact of metformin on blood glucose and insulin is well documented, its effects on other systemic physiologic and inflammatory factors are unknown. We completed a neoadjuvant "window of opportunity" study of metformin in non-diabetic women with BC and a series of analyses were performed on plasma samples to assess the impact of metformin on circulating inflammatory markers, growth factors, and tumor associated antigens.

Methods: Non-diabetic women with early stage, untreated BC were given metformin 500 mg tid for ≥2 weeks post diagnostic core biopsy until surgery. Fasting blood was collected at diagnosis and surgery to assess circulating markers pre- and post-metformin administration. Plasma was isolated from blood samples and evaluated for CRP, TNF-alpha, IL-6, IL-8, VEGF, EGF, PlGF (placenta growth factor), CA15-3, and SHBG (sex hormone binding globulin). Change scores (post-metformin minus pre-) were calculated and the degree of change characterized by the median change and the rank-biserial correlation. The Wilcoxon signed-rank test was used to test the null hypothesis that the change scores were symmetrically distributed around zero versus more positive or negative change.

Results: A total of 39 patients (mean age 51 years) completed the study and received metformin for a median of 18 days (range 13-40). Metformin was associated with changes in the levels of growth factors, with increases seen in EGF (median increase 1.1 pg/mL, r=0.42, p=0.027) and VEGF (1.7 pg/mL, r=0.31, p=0.09). A reduction in PlGF levels (-0.18 pg/mL, r=-0.6, p=0.0028) was also observed. The tumor associated antigen CA15-3 was significantly reduced after metformin treatment (-0.4 pg/mL, r=-0.56, p=0.0024) and a marker of sex hormone bioavailability (SHBG) was increased (2 nM, r=0.30, p=0.1). For circulating inflammatory markers, a significant increase in the levels of IL-8 (0.8 pg/mL, r=0.36, p=0.048) was observed, but changes in TNF-alpha and IL-6 were minimal (TNF-alpha 0.2 pg/mL, r=0.20, p=0.29; IL-6 0.1 pg/mL, r=0.14, p=0.46) and no change was seen in CRP (0 mg/L, r=-0.05, p=0.93).

Conclusions: Short-term metformin administration was associated with alterations in systemic physiologic and inflammatory factors. Such increases in circulating cytokines and growth factors indicate possible alterations in the inflammatory state of the host and/or tumor. Of note, the reduction seen in the tumor antigen CA15-3 may reflect a disease-modifying effect of metformin in BC.

The authors wish to acknowledge the generous support of the Hold'Em For Life Charity Challenge and the Breast Cancer Research Foundation.

Citation Format: Dowling RJ, Niraula S, Chang MC, Ennis M, Stambolic V, Goodwin PJ. Circulating inflammatory markers, growth factors, and tumor associated antigens in women with early stage breast cancer receiving neoadjuvant metformin [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-02-03.

Abstract P1-03-01: An international multicenter study to evaluate reproducibility of automated scoring methods for assessment of Ki67 in breast cancer

Background: The nuclear proliferation biomarker Ki67 has multiple potential roles in breast cancer, including prognosis-based decisions, but unacceptable between-laboratory variability has limited its clinical value. The International Ki67 Working Group (IKWG) has undertaken a systematic program to determine whether Ki67 immunohistochemistry can be analytically validated and standardized across laboratories. Technological advances and broader availability of devices for automated assessment of stained slides raise the possibility that these machines may improve on reproducibility of traditional pathologist-based visual Ki67 assessment.

Aims: To characterize reproducibility of automated machine-measured Ki67 expression using slides previously analyzed in the IKWG phase 3 study that evaluated reproducibility of visual Ki67 assessment.

Methods: Two sets of 30 previously stained slides containing core-cut biopsy sections of breast tumors were circulated to 14 laboratories for scanning and automated assessment of Ki67 expression. Sites were instructed to return average and maximum percentage of tumor cells positive for Ki67 for each slide, where maximum is designed to reflect “hot spot” analysis. Two laboratories returned scores from 2 operators; not all laboratories reported values for maximum Ki67 scores. Different operators were treated as distinct laboratories in analyses. Sixteen and 10 score sets were available for average and maximum Ki67 analyses, respectively, encompassing 7 unique scanner and 10 software platforms. Pre-specified analyses included evaluation of reproducibility across all laboratories as well as within a subgroup limited to those using Aperio scanners. The primary reproducibility metric was intraclass correlation coefficient between laboratories (ICC), regardless of device platform or software.

Results: Geometric means across 30 cases for 16 operators ranged from 11.06% to 38.11% with overall mean 16.75% (95% CI:14.45-19.42) for average scores. Geometric means for 10 operators ranged from 16.44% to 68.73% with overall mean 25.16% (95% CI: 18.71-33.84) for maximum scores. ICC for automated average scores across 16 operators was 0.83 (95% CI: 0.73-0.91) and ICC for maximum scores across 10 operators was 0.63 (95% CI: 0.44-0.80) although one outlier lab dramatically affected results. For the laboratories using the Aperio platform (8 score sets), ICC for automated average scores was 0.89 (95% CI; 0.81-0.96). These results are similar to ICC of 0.87 (95%CI; 0.81-0.93) reported using these same slides in the Phase 3 visual assessment reproducibility study in which observers counted 500 cells per slide (Leung et al, NPJBrCancer, in press).

Conclusions: Between-laboratory reproducibility for automated machine assessment of average Ki67 is similar to that for pathologist-based visual assessment of Ki67. However, the observed ICC was markedly numerically lower for the maximum score method compared to the average method, suggesting that the maximum score may not be useful as a reproducible measure of proliferation. Automated average scoring methods show promise for standardization of Ki67 scoring, supporting future studies to clinically validate Ki67.

Citation Format: Rimm DL, McShane LM, Leung SCY, Bai Y, Bane AL, Bartlett JMS, Bayani J, Chang MC, Dean M, Denkert C, Enwere E, Galderisi C, Gholap A, Hugh JC, Jadhav A, Kornaga E, Laurinavicius A, Levenson R, Lima J, Miller K, Pantanowitz L, Piper T, Ruan J, Srinivasan M, Virk S, Wu Y, Yang H, Hayes DF, Nielsen TO, Dowsett M. An international multicenter study to evaluate reproducibility of automated scoring methods for assessment of Ki67 in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-03-01.

Abstract P6-09-04: Nuclear grade has a limited role in predicting recurrence in DCIS following breast conserving surgery: A population-based study

This abstract was not presented at the symposium.

Abstract P5-05-01: Prevalance of crown-like structures of the breast, a histologic biomarker linked to obesity: A retrospective study of 99 cases

Introduction: Breast cancer risk is multifactorial, and depends partly on obesity and related metabolic imbalances, including inflammation. Obesity is increasing worldwide, and is a known cancer risk albeit with complex mechanisms. Previous reports (Morris et al., 2011; Iyengar et al., 2015) indicate that local inflammation can be seen histologically as a rings of macrophages around necrotic adipocytes ("crown-like structures of the breast", CLS-B). Our goal was to determine the prevalence of CLS-B in routine specimens from a cohort of patients with known BMI.

Methods: We retrieved archival H&E slides from a breast cancer cohort (N=99) previously characterized for BMI and fasting plasma/serum metabolic factors. Two pathologists reviewed all available sections of white adipose tissue not adjacent to tumour (median 7 blocks/case), excluding fat necrosis and mastitis, blinded to correlative data/BMI. We recorded the presence/absence and numbers of CLS-B, defined as a continuous ring of macrophages surrounding an adipocyte. Paraffin blocks were available in a subset (N=72) and a representative block was immunostained for CD68 to highlight CLS-B. For all cases, the average fat vacuole size was determined by digital image analysis (NIH ImageJ Software). We performed correlative statistics between CLS-B status and clinical data (χ2, Wilcoxon rank-sum tests).

Results: CLS-B were present in 37 of 99 cases (37%). When present the total number of CLS-B ranged from 1 to 18 (mean=4.3, median=3). CLS-B were detected in 7/10 (70%) patients with BMI &gt;30 vs. 30/89 (34%) with BMI ≤ 30 (p=0.02). CLS-B also trended to higher prevalence in women over 60 compared to women under 60 (12/20, 60% vs. 25/79, 32%, p = 0.063). There was no significant association of CLS-B status with tumor T- and N-stage or grade (all P&gt;0.4). The median C-reactive protein in the group with CLS-B was 1.5 mg/L vs. 0.8 mg/L in the group without CLS-B (P=0.10) There was no significant association of CLS-B with insulin, glucose, HOMA, leptin, adiponectin, total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, or IGF-1 (all P&gt;0.27). The average fat globule area determined by image analysis correlated significantly with BMI (Spearman correlation 0.54, p&lt;0.0001) but not to the presence of CLS-B (p=0.102).

Within the subset immunostained for CD68, 32/72 (44%) had CLS-B on the original H&E sections, whereas 13/72 (18%) had CLS-B on the representative CD68-stained section. This corresponded to a false negative in 22/59 (37%) CD68-negative cases, and increased detection in 3/13 of the CD68-positive cases.

Conclusion: In our cohort, obesity is correlated with elevated tissue inflammation as seen by the presence of CLS-B, but CLS-B is not correlated with metabolic markers. CLS-B are well appreciated on routine H&E sections; however, more work is needed to find a practical approach to both ancillary testing (e.g. CD68) and quantitation. Our work independently confirms the association of CLS-B with obesity, and supports the concept that CLS-B is a tissue biomarker of obesity-related inflammation.

(Z.E. was co-principal author.)

Citation Format: Chang MC, Eslami Z, Ennis M, Goodwin PJ. Prevalance of crown-like structures of the breast, a histologic biomarker linked to obesity: A retrospective study of 99 cases. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-05-01.

Abstract P2-02-09: Obesity associated factors are inversely associated with circulating tumor cells in metastatic breast cancer

Background: Elevated levels of circulating tumor cells (CTCs) are associated with adverse outcomes in metastatic breast cancer (BC). However, relationships between CTCs and various patient-related factors that may impact outcome remain undefined. Consequently, associations of CTC counts with obesity and metabolic factors were evaluated in order to gain insight into potential interactions between patient physiology and disease burden. We hypothesized that obesity and associated metabolic factors would be associated with higher CTC counts.

Methods: Non-diabetic women with metastatic BC beginning a new line of treatment due to progressive disease were recruited from four Ontario cancer hospitals between February 2013 and April 2015. Patients provided blood for CTC analysis, which was completed within 72 hours of collection using the Janssen CellSearch platform. Fasting serum was also collected for assessment of metabolic factors including glucose (mmol/L), insulin (pmol/L), leptin (ng/mL) and adiponectin (ng/mL). Associations of CTC counts with these factors, as well as anthropometric measurements (height (cm), weight (kg), BMI (kg/m2)) were evaluated using Pearson correlation coefficients after transforming the variables involved to normality. For CTC counts, the log transformation with half integer correction was used.

Results: 96 patients with a median age of 60.5 years completed the study. Most were post-menopausal (87, 90.6%) and exhibited grade II/III tumors (75, 78.1%). The majority of patients had hormone receptor positive disease (83, 86.5%), but 16.7% (16) were HER2 positive and 10.4% (10) were triple negative. The number of CTCs observed ranged from 0 to 1238 (median 2, geometric mean 3.63). No CTCs were detected in 29 patients (30.2%), whereas 25 patients (26 %) exhibited counts of 1 to 4 CTCs and 42 (43.8%) had 5 or more CTCs. CTCs were not significantly associated with tumor characteristics including ER/PgR, HER2, grade, stage (T/N) or lymphovascular invasion. The number of CTCs inversely correlated with BMI (r=-0.26, p=0.01), leptin (r=-0.29, p=0.004), and leptin-adiponectin ratio (r=-0.3, p=0.004). A similar trend that approached significance was noted for body weight (r=-0.19, p=0.07), insulin (r=-0.19, p=0.06) and homeostatic model assessment (HOMA, an estimate of insulin resistance, r=-0.2, p=0.055). Conversely, adiponectin (r=0.18, p=0.07) and height (r=0.18, p=0.07) were positively associated with CTC counts in correlations that neared significance. No associations were observed for age (r=0.09, p=0.4) or glucose (r=-0.09, p=0.4).

Conclusions: Obesity associated metabolic factors including weight, BMI, insulin, HOMA and leptin were inversely associated (and adiponectin and height positively associated) with CTC counts. These patterns are consistent with weight loss and/or cachexia in women with elevated CTC counts who have higher disease burden. Additional analyses are underway to further characterize these associations and include assessment of serum albumin, free fatty acids, creatine kinase and hepcidin.

Citation Format: Dowling RJO, Chang MC, Lohmann AE, Ennis M, Amir E, Elser C, Brezden-Masley C, Vandenberg T, Lee E, Fazaee K, Stambolic V, Goodwin PJ. Obesity associated factors are inversely associated with circulating tumor cells in metastatic breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-02-09.

Genetic testing for BRCA1 and BRCA2 in the Province of Ontario

In 2001, genetic testing for BRCA1 and BRCA2 was introduced in Ontario, for women at high-risk of breast or ovarian cancer. To date over 30,000 individuals have been tested throughout Ontario. Testing was offered to all Ontario residents who were eligible under any of 13 criteria. We report the results of tests conducted at Mount Sinai Hospital from 2007 to 2014. A total of 4726 individuals were tested, 764 (16.2%) were found to carry a pathogenic variant (mutation). Among 3684 women and men who underwent testing without a known familial BRCA mutation, 331 (9.0%) were found to carry a mutation. Among 1042 women and men tested for a known family mutation, 433 (41.6%) were positive. There were 603 female mutation carriers, of these, 303 were affected with breast or ovarian cancer (50%) and 16 with another cancer (2.3%). Of 284 unaffected female carriers, 242 (85%) were tested for a known family mutation and 42 (15%) were the first person in the family to be tested. By placing greater emphasis on recruiting unaffected female relatives of known mutation carriers for testing, greater than one-half of newly identified carriers will be unaffected.

Abstract P2-10-07: Ep-ICD overexpression associates with poor prognosis in invasive ductal carcinoma

Background: Despite improvements in treatment strategies recurrence rates are still high among breast cancer patients. This may be attributed to heterogeneous nature of breast cancers representing varied morphologic and biological features, behavior, and response to therapy. Even among breast tumors of similar histologic type and grade, prognosis varies. Currently, breast cancer prognosis assessment methods have limited accuracy, are expensive, and in 20-30% of cases lead to over-treatment with adverse effects. None of the currently known prognostic factors has the ability to predict accurately which breast cancer patients are at high risk of recurrence. Thus, there is an increasing need for identification and validation of prognostic markers for assessment of risk for disease recurrence in breast cancer patients.

Epithelial cell adhesion molecule (EpCAM) is a glycosylated, 30- to 40-kDa type I membrane protein, expressed in several human epithelial tissues and overexpressed in cancers, as well as in progenitors, normal and cancer stem cells, and is implicated in epithelial mesenchymal transition (EMT). Regulated intra-membrane proteolysis (RIP) of EpCAM by tumor-necrosis-factor alpha converting enzyme (TACE) results in shedding of its extracellular domain (EpEx) and release of intracellular domain, Ep-ICD, into the cytoplasm. Ep-ICD can signal into the cell nucleus by engagement of components of the Wnt pathway proteins including four and one half LIM domains protein 2 (FHL2), β-catenin and Lef, leading to activation of its oncogenic activity.

Objective. Evaluate the prognostic significance of Ep-ICD overexpression in invasive ductal carcinoma (IDC).

Methodology: Formalin fixed paraffin embedded (FFPE) tissue sections obtained from IDCs (n = 180) and normal breast tissues (n = 45) were used for immunostaining for Ep-ICD using specific monoclonal antibody. A semi-quantitative visual scoring of the immunostaining results for Ep-ICD based on percentage of tumor cells stained and intensity of scoring was used to compare the expression in breast cancers and normal tissues. Statistical analysis was carried out to determine the association of Ep-ICD expression with clinical outcome.

Results: Among the 180 IDCs analyzed, nuclear Ep-ICD was observed in 75 tissues (41.7%) while cytoplasmic positivity was observed in 145 tissues (80.6%). In comparison, nuclear Ep-ICD localization was observed only in 11 normal tissues (23.9%) and cytoplasmic positivity was observed in 39 normal tissues (86.7%). The nuclear / cytoplasmic Ep-ICD expression has been correlated with at least 5 years follow-up data of 180 breast cancer patients after primary treatment. Kaplan Meier survival analysis showed significantly reduced 5 year disease free survival in IDC patients showing nuclear positivity (p &lt; 0.001) or cytoplasmic positivity (p = 0.048). In Cox multivariate regression analysis, nuclear Ep-ICD overexpression emerged as an independent indicator of poor prognosis in IDCs (p = 0.008, H.R. = 81.18).

Conclusion: Among invasive ductal carcinomas of the breast, nuclear Ep-ICD overexpression predicts reduced 5-year disease free survival.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-10-07.

Abstract PD03-05: Analysis of tumour cell signaling in response to neoadjuvant metformin in women with early stage breast cancer

Background: The anti-diabetic drug metformin, commonly used to treat type 2 diabetes due to its ability to reduce circulating glucose and insulin, has emerged as a potential anti-cancer agent. Observational studies have reported decreased cancer incidence and mortality in diabetics receiving metformin. Metformin's ability to reduce insulin may be particularly important for breast cancer (BC) because hyperinsulinemia is an adverse prognostic factor and most cells express the insulin receptor (IR). The anti-cancer effects of metformin are associated with both direct (insulin-independent) and indirect (insulin-dependent) actions. Direct effects are linked to activation of AMPK and an inhibition of mTOR signalling, while indirect effects are mediated by reductions in circulating insulin levels, leading to reduced IR-activated PI3K signalling. We conducted a neoadjuvant, single arm, “window of opportunity” trial examining the clinical and biological effects of metformin on thirty-nine locoregional BC patients awaiting definitive surgery.

Methods: Non-diabetic women with newly diagnosed, untreated BC were given metformin 500 mg tid for ≥2 weeks post diagnostic core biopsy until surgery. Fasting blood and tumour samples were collected at diagnosis and surgery. Blood glucose and insulin were assayed to assess the physiologic effects of metformin, while IHC analysis of tumours was used to characterize cellular markers before and after metformin. Specifically, IR levels and the phosphorylation status of proteins involved in AMPK and PI3K/AKT/mTOR signalling, including AMPK (T172) and AKT (S473), were examined.

Results: 39 patients with a mean age of 51 years received metformin for a median of 18 days (range 13–40) with minor GI toxicities. The clinical effects (previously reported) included significant (p &lt; 0.05) decreases in body mass index (−0.5 kg/m2), weight (−1.2 kg), glucose (−0.14 mM) and HOMA (an estimate of insulin resistance, −0.21), and a decrease in insulin (−4.7 pmol/L) that approached significance (p = 0.0686). Ki67 staining in tumour tissue decreased significantly and TUNEL increased significantly. Levels of IR expression decreased significantly (from 4.39 to 3.82, p = 0.0375) as did the phosphorylation status of AKT (S473) and AMPK (T172) (from 9.82 to 7.08, p = &lt;0.0001; from 6.2 to 5.1, p = 0.0034, respectively).

Conclusions: Metformin impact was consistent with beneficial anti-cancer effects. Reduced AKT phosphorylation, coupled with decreased insulin and IR levels, suggest insulin-dependent effects are important in the clinical setting. Assessment of additional factors in BC cells, including OCT1 expression (required for metformin uptake), and the phosphorylation of ACC (a marker of AMPK activation), is underway and will be reported. Integrated analysis of these factors combined with the physiological and molecular data described above will further enhance understanding of metformin action in the clinical setting.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD03-05.

Abstract P2-10-09: The incidence of false negative of HER2/Neu status in primary breast cancer in the era of standardized testing: a Canadian prospective study

The efficacy of trastuzumab in the treatment of primary breast cancer has mandated accurate and timely testing of all patients with a new diagnosis of breast cancer. Testing is centralized in designated laboratories across Canada with adherence to guidelines and mandatory participation in quality assurance programs. The Canadian testing algorithm recommends starting with immunohistochemistry (IHC) followed by in situ hybridization (ISH) for equivocal cases. Early HER2 testing showed that approximately 25–30% of invasive breast cancer is HER2 positive. Recent data shows that the HER2/neu positive rate in breast cancer in Canada is 17.6%.

Design: The study was designed to assess the rate of false-negative HER2 tests based on the IHC-first algorithm used in 8 pathology centres across Canada. Surgical excisions with invasive carcinoma were tested using the standardized local methodology for both IHC and ISH. The cases were scored by the local breast pathologist and in 2 of 8 centers image analysis was used in the evaluation of ISH. We compared consecutive HER2-negative IHC results (score 0/1+) to the corresponding ISH (either silver or fluorescence) result. False negative cases were defined as a negative IHC with an ISH ratio of≥ 2, since these patients are eligible for trastuzumab therapy.

Results: 715 cases were analyzed by IHC using Ventana 4B5 (287), HercepTest (253), or SP3 (175), and by ISH kits: Vysis FISH (303), Ventana SISH (412). The HER2 and CEP17 counts were available in all cases.

There were 4 cases with an ISH score ≥2 (4B5: 2/4, HercepTest 1/4, SP3 1/4). In 3 additional cases the absolute HER2 copy number was ≥6 but the HER2/CEP17 amplification ratio was &lt;2 due to an increased number of CEP 17 signal (“polysomy 17”) or amplification of the pericentromeric region. The overall rate of false negative cases was 0.98% (7/715). These cases had a low level of amplification (ratio 2 to 2.45) or an absolute HER2 count of 6–8.

Conclusion: Our observation confirms that IHC is an adequate test to predict negative HER2 status in primary breast cancer in surgical excision specimens, even when different antibodies and IHC platforms are used. The study supports and justifies the Canadian algorithm of IHC followed by ISH in equivocal cases in view of the extremely low percentage of false negative cases observed. This reflects the strict adherence to internal protocols and mandatory participation in quality assurance programs. These results provide further confirmation that the vast majority of patients eligible for trastuzumab are not deprived from an effective treatment by using this algorithm.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-09.

Abstract PD03-02: Evidence for the anti-cancer action of metformin mediated via tumor AMPK, Akt and Ki67, in a preoperative window of opportunity trial

Background: Metformin reduces the overall risk of cancer incidence by 31%, improves cancer-related mortality and enhances response to neoadjuvant chemotherapy in type 2-diabetics receiving metformin. There is evidence that metformin works through activation of Adenosine Monophosphate Protein Kinase (AMPK), an energy-sensing kinase that maintains cellular energy homeostasis. In a pre-operative window-of-opportunity randomized trial we have demonstrated that metformin significantly reduces proliferation and blunts the insulin response in primary operable breast cancer. This study further analysed cancer tissue from the trial to dissect the molecular mechanisms involved.

Methodology: Non-diabetic women with operable invasive breast cancer were randomised to receive pre-operative metformin or no drug. Forty seven patients had core biopsy at diagnosis then were randomized to metformin (metformin 500mg o.d. for 1 week increased to 1g b.d for a further week continued to surgery) or no drug, and 2 weeks later had core biopsy at surgery. Insulin receptor, phospho-AMPK (pAMPK), phospho-Akt (pAkt) and Ki67 immunohistochemistry was performed on formalin-fixed paraffin-embedded cores and scored blinded to treatment. Paired t-test was used for analysis.

Results: Significant up-regulation of pAMPK (p = 0.04) and down-regulation of pAkt (p = 0.04) in metformin treated patients was demonstrated compared to the control group. No change in insulin receptor expression was identified but, as previously reported, there was a fall in ki67. Changes were independent of Body Mass Index. Seven patients (7/24) receiving metformin withdrew because of gastro-intestinal upset and were excluded from the immunohistochemical analyses.

Conclusion: These findings suggest that metformin works in vivo in breast cancer patients via up-regulation of tumor pAMPK and down-regulation of pAkt and proliferation. Since down-regulation of pAMPK is a feature of breast cancer, this suggests mechanistic evidence for the therapeutic effect of metformin.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD03-02.

Catechin stimulates osteogenesis by enhancing PP2A activity in human mesenchymal stem cells

SUMMARY

Using human mesenchymal stem cells, we identified catechin from a panel of herbal ingredients and Chinese traditional compounds with the strongest osteogenic effects. Catechin increased alkaline phosphatase activity, calcium deposition, and mRNA expression of Runx2 and osteocalcin. We further clarified the signaling pathway that catechin mediated to stimulate osteogenesis.

INTRODUCTION

Human mesenchymal stem cells (hMSCs), useful as a species specific cell culture system for studying cell lineage differentiation, were examined as a tool to identify novel herbal ingredients and Chinese traditional compounds for enhancing osteogenesis.

METHODS

Immortalized and primary hMSCs were induced in osteogenic induction medium in the presence of a variety of herbal ingredients and Chinese traditional compounds and osteogenic differentiation was evaluated by histochemical assays and quantitative RT-PCR.

RESULTS

Using immortalized hMSCs, we first identified catechin, 18β-glycyrrhetinic acid, baishao, and danggui with osteogenic properties, which enhanced calcium deposition at the dose without significant cytotoxic effects. Primary hMSCs were then applied for confirming the osteogenic effects of catechin, which increased alkaline phosphatase activity, calcium deposition, and mRNA expression of Runx2 and osteocalcin. We further found the extracellular signal-regulated kinase (ERK) pathway was downregulated upon stimulation with catechin. Catechin increased the level and activity of protein phosphatases 2A (PP2A) that dephosphorylates ERK kinase (MEK) and ERK. Further, PP2A inhibitor, okadaic acid, abolished the effect of catechin-mediated inactivation of ERK and stimulation of osteogenesis. The blocking effect of okadaic acid on osteogenesis was further reversed by PD98059, a specific inhibitor of MEK. Co-immunoprecipitation revealed the association of PP2A to both MEK and ERK.

CONCLUSIONS

These studies propose catechin enhanced osteogenesis by increasing the PP2A level that inhibits the MEK and ERK signaling in hMSCs. These results prove the concept of using hMSCs as a convenient tool for rapid and consistent screening of the osteogenic herbal ingredients and traditional Chinese compounds.

Overview Of Process Integration Issues For Low K Dielectrics

The era of silicon Ultra-Large-Scale-Integration (ULSI) has spurred an everincreasing level of functional integration on-chip, driving a need for greater circuit density and higher performance. While traditional transistor scaling has thus far met this challenge, interconnect scaling has become the performance-limiting factor for new designs. Both interconnect resistance and capacitance play key roles in overall performance, but modeling simulations have highlighted the importance of reducing parasitic capacitance to manage crosstalk, power dissipation and RC delay. New dielectric materials with lower permittivity (k) are needed to meet this challenge. This paper summarizes the process integration and reliability issues associated with the use of novel low k materials in multilevel interconnects.

Effect of protozoa on bacterial degradation of an aromatic compound

Prototrophic and growth factor-requiring strains of Alcaligenes spp. were used to study the effect of a protozoan, Tetrahymena pyriformis, on the degradation of p-aminobenzoate. The protozoan inhibited activity of the prototrophic bacterium by reducing its population size. For the growth factor-requiring strain of Alcaligenes, T. pyriformis provided the required growth factors so that the predator permitted the bacteria to grow and to continue p-aminobenzoate degradation. T. pyriformis inhibited bacterial activity when the amino acid supply was in excess, but activity of the auxotrophic strain of Alcaligenes was stimulated by the protozoan when the amino acid supply was limiting, although the bacterial population size was reduced by the protozoan.

THE EFFECTS OF SERUM ON SPERMATOZOA

A spermicidal factor was found in fresh human, bovine, rabbit, guinea pig, and rat sera. It kills the spermatozoa of its own species (except in the case of human serum) and the sperms of other species. It was unstable, thermolabile, and of large molecular size. It was present in limited quantity in the fresh serum and could be used up by a definite number of spermatozoa. It could be destroyed by sodium citrate, by Seitz filtration, by trypsin, and by snake venom. This factor was not present in tissue extracts and various plasma protein fractions. The strength or concentration of this factor varies in different individuals and in different species. This factor has several characteristics similar to those of complement.

Primary ex vivo cultures of human fallopian tube epithelium as a model for serous ovarian carcinogenesis

Recent studies suggest that some serous ovarian carcinomas (SOCs) arise from the fallopian tube (FT) epithelium rather than the ovarian surface epithelium. This hypothesis places emphasis on the FT secretory epithelial cell as a cell-of-origin. Herein, we report the development of a novel ex vivo primary human FT epithelium culture system that faithfully recapitulates the in vivo epithelium, as shown by morphological, ultrastructural and immunophenotypic analyses. Mass spectrometry-based proteomics reveal that these cultures secrete proteins previously identified as biomarkers for ovarian cancer. We also use this culture system to study the response of the FT epithelium to genotoxic stress and find that the secretory cells exhibit a distinct response to DNA damage when compared with neighboring ciliated cells. The secretory cells show a limited ability to resolve the damage over time, potentially leaving them more susceptible to accumulation of additional mutagenic injury. This divergent response is confirmed with in situ studies using tissue samples, further supporting the use of this ex vivo culture system to investigate FT epithelial pathobiology. We anticipate that this novel culture system will facilitate the study of SOC pathogenesis, and propose that similar culture systems could be developed for other organ site-specific epithelia.

Taiwan's population and family planning efforts: an historical perspective

The unprecedented decline of Taiwan's natural population increase rate from 3% in 1963 to 1.9% in 1973, attributed primarily to an increasing use of contraception, brought universal attention to one of the first and most successful national family planning programs, at a time when successes were few. Taiwan met its goal of decreasing its natural increase rate despite its young population, increasing numbers of women of childbearing ages, a strong preference for sons and a per capita income at the outset in 1963 of less than U.S.$200. Recognition of this achievement brought thousands of professionals, particularly from developing countries, to study the program firsthand: more than 3,000 during 1970--73 alone. This was matched by an avalanche of publications about the program that appeared around the world, written by practitioners, academics and others. This article tells the story of this success.

Antioxidant and pro-oxidant properties of chlorhexidine and its interaction with calcium hydroxide solutions

AIM

To evaluate the antioxidant and pro-oxidant properties of chlorhexidine (CHX).

METHODOLOGY

The scavenging and generation of reactive oxygen species (ROS) by CHX in the presence or absence of saturated Ca(OH)(2) solutions was evaluated. The reaction emitted chemiluminescence in the presence of lucigenin thus was determined by a luminometer to evaluate the levels of ROS production. Changes in DNA conformation were analysed by agarose gel electrophoresis. Paired Student's t-test was used to compare the difference between groups.

RESULTS

Chlorhexidine (0.00002-0.02%) effectively scavenged 56-88% of the superoxide radicals generated by the xanthine/xanthine oxidase reaction. Through analysis of PUC18 DNA conformation changes, CHX was shown to be a mild scavenger of hydroxyl radicals generated by H(2)O(2) plus FeCl(2). However, CHX (>0.083%) decreased the mobility of PUC18 plasmid DNA with potential production of DNA-DNA cross-link and severe DNA breaks (presence of DNA smear) at further higher concentrations. Furthermore, CHX induced ROS production including H(2)O(2) and superoxide radicals in 0.1N NaOH (pH = 12.76) or Ca(OH)(2) (pH = 12.5) solutions.

CONCLUSION

Chlorhexidine exhibited both antioxidant and pro-oxidant properties under different conditions. These events are possibly involved in the killing of root canal and periodontal microorganisms when CHX and Ca(OH)(2) were used in combination or separately. Potential genotoxicity and tissue damage when extruded into the periradicular tissue and at higher concentrations should be considered during periodontal and endodontic practice.

Hydroxychavicol, a novel betel leaf component, inhibits platelet aggregation by suppression of cyclooxygenase, thromboxane production and calcium mobilization

BACKGROUND AND PURPOSE

Platelet hyperactivity is important in the pathogenesis of cardiovascular diseases. Betel leaf (PBL) is consumed by 200-600 million betel quid chewers in the world. Hydroxychavicol (HC), a betel leaf component, was tested for its antiplatelet effect.

EXPERIMENTAL APPROACH

We tested the effect of HC on platelet aggregation, thromboxane B(2) (TXB(2)) and reactive oxygen species (ROS) production, cyclooxygenase (COX) activity, ex vivo platelet aggregation and mouse bleeding time and platelet plug formation in vivo. The pharmacokinetics of HC in rats was also assessed.

KEY RESULTS

HC inhibited arachidonic acid (AA) and collagen-induced platelet aggregation and TXB(2) production. HC inhibited the thrombin-induced TXB(2) production, but not platelet aggregation. SQ29548, suppressed collagen- and thrombin-induced TXB(2) production, but not thrombin-induced platelet aggregation. HC also suppressed COX-1/COX-2 enzyme activity and the AA-induced ROS production and Ca(2+) mobilization. HC further inhibited the ex vivo platelet aggregation of platelet-rich plasma (>100 nmole/mouse) and prolonged platelet plug formation (>300 nmole/mouse) in mesenteric microvessels, but showed little effect on bleeding time in mouse tail. Moreover, pharmacokinetics analysis found that more than 99% of HC was metabolized within 3 min of administration in Sprague-Dawley rats in vivo.

CONCLUSIONS AND IMPLICATIONS

HC is a potent COX-1/COX-2 inhibitor, ROS scavenger and inhibits platelet calcium signaling, TXB(2) production and aggregation. HC could be a potential therapeutic agent for prevention and treatment of atherosclerosis and other cardiovascular diseases through its anti-inflammatory and antiplatelet effects, without effects on haemostatic functions.

The feasibility study of using non-woven MBR for reduction of hydrolysed biosolids

In this study, non-woven MBR was used to treat hydrolysed biosolids wasted from a biological treatment plant. The concentration of SS of hydrolysed biosolids in influent was 10,000 mg/L and the concentration of SS in effluent was less than 200 mg/L with/without discharging wasted sludge depending on different HRTs, i.e. 20, 15 and 10 d. The results indicated that the percentage of biosolids reduction in terms of SS removal efficiency in non-woven MBR was around 65, 60 and 35%, respectively, depending on different HRTs. Meanwhile, the ratio of VSS/SS was decreased from 0.78 to 0.50 and the number of smaller inorganic particle sizes increased due to extended SRT. The initial flux in the non-woven MBR was set at 0.02, 0.04 and 0.06 m3/m2/day and trans-membrane pressure (TMP) was less than 10 kPa. The permeate flux could be maintained quite stably due to lower TMP. The proposed non-woven MBR could be used to achieve the reduction of biosolids in the wastewater treatment plant.

Cell-mediated immunity and head and neck cancer: with special emphasis on betel quid chewing habit

Betel quid (BQ) chewing is popular in Taiwan, India, and many southeast-Asian countries. BQ chewing has strong association with the risk of oral leukoplakia (OL), oral submucous fibrosis (OSF), and oral cancer (OC). BQ components exhibit genotoxicity and may alter the structure of DNA, proteins and lipids, resulting in production of antigenicity. BQ ingredients are also shown to induce keratinocyte inflammation by stimulating the production of prostaglandins, TNF-alpha, IL-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in keratinocytes. These events may provoke tissue inflammation, early cell-mediated immunity (CMI), and immune surveillance in BQ chewers. However, BQ components also directly affect the functional activities of immunocompotent cells, and moreover tumor cells may hypo-respond to the CMI via diverse mechanisms such as induction of apoptosis of lymphocytes, induction of production of suppressor T cells, downregulation of MHC molecules in tumor cells, etc. Clinically, an alteration in lymphocyte subsets, a decrease in total number of lymphocytes, and a reduction in functional activities of CMI have been observed in isolated peripheral blood mononuclear cells (PBMC) and tumor infiltrated lymphocytes (TIL) in patients with OSF, OL or OC. Adaptation of tumor cells to immune system may promote clonal selection of resistant tumor cells, leading to immune tolerance. Future studies on effects of BQ components on CMI and humoral immunity in vitro and in vivo can be helpful for chemoprevention of BQ-related oral mucosal diseases. To elucidate how virus infection, tobacco, alcohol and BQ consumption, and other environmental exposure affect the immune status of patients with oral premalignant lesions or OC will help us to understand the immunopathogenesis of OC and to develop immunotherapeutic strategies for OC.

Effects of TGF-beta s on the growth, collagen synthesis and collagen lattice contraction of human dental pulp fibroblasts in vitro

Transforming growth factor-beta (TGF-beta) is important in regulating the repair and regeneration of damaged dental pulp. For further elucidating the roles of different isoforms of TGF-beta in the healing and inflammatory processes of human dental pulp, we found that TGF-beta1, TGF-beta2 and TGF-beta3 inhibited the growth of two human dental pulp cell strains in vitro by 19-29, 18-25 and 23-26%, respectively, at a concentration of 0.5 ng/ml. TGF-beta also differentially stimulated the collagen synthesis of pulp cells. Collagen synthesis increased by 1 ng/ml of TGF-beta1 and TGF-beta2 by 42 and 51%, respectively. TGF-beta3 (0.1-1 ng/ml) lacked of stimulatory effect on collagen synthesis of pulp cells. Pulp cells have the intrinsic capacity to contract collagen lattice, leading to decreasing of lattice diameter. An 8 h exposure to TGF-beta1 and TGF-beta2 enhanced the pulp cell-populated collagen lattice contraction at concentrations ranging from 0.2 to 3 ng/ml. At similar concentrations, TGF-beta3 lacked of this stimulatory effect. When collagen lattice were detached after 24 h of exposure, TGF-beta1 and TGF-beta2 (0.6-3 ng/ml) induced the pulp cells-populated collagen lattice contraction within 4-8h of gel detachment. These results indicate that TGF-beta-induced collagen lattice contraction is a late cellular event. These in vitro results indicate that effects of TGF-beta isoforms on the growth, collagen synthesis and collagen lattice contraction of pulp cells may play crucial roles in the pathobiological processes of dental pulp.

Reactive oxygen species are crucial for hydroxychavicol toxicity toward KB epithelial cells

Betel quid (BQ) chewing shows a strong correlation to the incidence of oral submucous fibrosis (OSF), leukoplakia and oral cancer. BQ contains mainly areca nut, lime, Piper betle leaf (PBL) and the inflorescence of P. betle (IPB). Hydroxychavicol (4-allyl-catechol, HC), as a major phenolic compound in PBL and IPB, is shown to induce oxidative stress, glutathione (GSH) depletion and cell cycle deregulation. Using bivariate BrdU/PI flow cytometry, KB cells in DNA synthesis (S phase) are shown to be sensitive to the toxic effect of HC and show cell cycle arrest and apoptosis following exposure to 0.1 and 0.3 mM HC. HC-induced apoptosis and cell cycle arrest are associated with mitochondrial membrane potential (delta Psim) depolarization as revealed by a decrease in rhodamine fluorescence. N-acetyl-L-cysteine (1 mM), superoxide dismutase (100 U/ml) and catalase (1000 U/ml) were effective in prevention of HC-induced GSH depletion (as indicated by chloromethylfluorescein fluorescence), reactive oxygen species (ROS) production (by dichlorofluorescein fluorescence), cell cycle arrest and apoptosis. However, dimethylthiourea (2 mM), neocuproine (1 mM), 1,10-phenanthroline (200 microM) and desferrioxamine (0.5 mM) showed little effect on HC-induced cell changes. HC elevated the cellular and mitochondrial GSH levels at moderate concentrations (0.05-0.1 mM), whereas at a concentration of 0.3 mM, inhibitory effects were noted. These results indicate that HC consumption may be associated with BQ-chewing-related oral mucosal diseases via GSH depletion, ROS production, mitochondrial dysfunction, cell cycle disturbance and the induction of apoptosis. These events are related to the production of superoxide radicals and hydrogen peroxide.

Factors affecting the stability of the performance of ambient fine-particle concentrators

This article describes a systematic evaluation of factors affecting the stability of the performance of Harvard ambient fine-particle concentrators, an essential requirement for controlled animal and human exposure studies that utilize these technologies. Phenomenological problems during the operation of the concentrator, including pressure drop increase and decrease in concentration enrichment, were statistically correlated with ambient air parameters such as temperature, relative humidity, PM2.5 mass concentration, and mass median diameter. The normalized hourly pressure drop across the concentrator was strongly associated (R2 = .81) with the product of ambient PM2.5 mass concentration and the difference between the vapor pressure downstream of the impactor nozzle and the saturation vapor pressure at the adiabatic expansion temperature (i.e., the temperature of the aerosol immediately downstream of the virtual impactors). From multiple regression analysis, the average enrichment factor was predicted reasonably well (R2 = .67) by aerosol mass median diameter and the normalized hourly pressure drop. Based on these results, we can anticipate in any given day whether an exposure study can be conducted without a considerable increase in the concentrator pressure drop, which might lead to an abrupt or premature termination of the exposure. As particle mass concentration and ambient dewpoint are the two main parameters responsible for raising the pressure drop across the concentrator, efforts should be made to either desiccate the ambient aerosol at days of high dewpoints, or to dilute the ambient PM at days of high concentrations, prior to drawing the aerosol through the virtual impactors. The latter approach is recommended on days of severe ambient pollution conditions because it is simpler and also makes it possible to maintain the appropriate concentration level delivered to the exposure chamber.

Elasticity of alveolar bone near dental implant-bone interfaces after one month's healing

Information is scarce about Young's modulus of healing bone surrounding an implant. The purpose of this preliminary study is to quantify elastic properties of pig alveolar bone that has healed for 1 month around titanium threaded dental implants, using the nanoindentation method. Two 2-year-old Sinclair miniswine were used for the study. Nanoindentation tests perpendicular to the bucco-lingual cross section were performed on harvested implant-bone blocks using the Hysitron TriboScope III. Nomarski differential interference contrast microscopy was used to identify pyramidal indentation measurements that were from bone. Reduced moduli, averaged for all anatomical regions, were found to start low (6.17 GPa) at the interface and gradually increase (slope=0.014) to a distance of 150 microm (7.89 GPa) from the implant surface, and then flatten to a slope of 0.001 from 150 to 1500 microm (10.13 GPa). Mean reduced modulus and its relationship to distance did not differ significantly by anatomic location (e.g., coronal, middle, and apical third; P>/=0.28 for all relevant tests) at 1 month after implantation.

Chronic lithium downregulates cyclooxygenase-2 activity and prostaglandin E(2) concentration in rat brain

Rats treated with lithium chloride for 6 weeks have been reported to demonstrate reduced turnover of arachidonic acid (AA) in brain phospholipids, and decreases in mRNA and protein levels, and enzyme activity, of AA-selective cytosolic phospholipase A(2)(cPLA(2)). We now report that chronic lithium administration to rats significantly reduced the brain protein level and enzyme activity of cyclooxygenase-2 (COX-2), without affecting COX-2 mRNA. Lithium also reduced the brain concentration of prostaglandin E(2) (PGE(2)), a bioactive product of AA formed via the COX reaction. COX-1 and the Ca(2+)-independent iPLA(2) (type VI) were unaffected by lithium. These and prior results indicate that lithium targets a part of the AA cascade that involves cPLA(2) and COX-2. This effect may contribute to lithium's therapeutic action in bipolar disorder.

Ambient fine and coarse particle suppression of alveolar macrophage functions

Alveolar macrophages (AM) are part of the innate immunological defense system and are among the first cells to respond to the effects of inhaled particles. Study of macrophage responses to particles is, therefore, relevant to understanding the mechanisms by which inhaled particles can adversely affect health. Size-fractionated ambient particles were collected at traffic-dominated sites in The Netherlands using a mobile high volume slit impactor system. AM were obtained by bronchoalveolar lavage from adult as well as aged rats and were incubated with for 4 h with collected particles at concentrations of 25-1000 pg per cell. Free radical generation by AM was measured with and without stimulation of AM with phorbol myristate acetate (PMA). There were dose-dependent decreases in macrophage production of superoxide radicals as measured by the chemiluminescent method. Coarse particles were more toxic than were fine particles. Suppression of free radical production did not seem to be related to the presence of bioavailable iron or to endotoxin associated with the particles. There were no statistically significant differences related to age or strain of the rats tested. We conclude that in vitro tests using AM is a useful and rapid method for delineating differences in toxicity between environmental samples of size fractionated ambient particles.

The cross-linkage effect of hydroxyapatite/collagen nanocomposites on a self-organization phenomenon

Hydroxyapatite(HAp)/collagen nanocomposites were prepared by a coprecipitation method controlling the degree of cross-linkage between collagen molecules using glutaraldehyde. The precipitates filtered were dried in a freeze drier or naturally dried in the air at 25 degrees C. The naturally dried cakes had open channels of 5-15 microm in diameters, which were three-dimensionally and regularly developed over the whole samples, and showed a pretty good mechanical strength. The channels that were formed at spaces among the HAp/collagen particles, cross-linked one another, which had been filled up with water before its evaporation. The ordering state of the open channels depended on the degree of cross-linkage with glutaraldehyde; the optimal self-organized state was found when 30 molecules of glutaraldehyde were added per collagen molecule, though an excess amount of glutaraldehyde suppressed the appearance of the ordered state. From SEM and FT-IR measurements, it was indicated that the self-organization in the HAp/collagen nanocompsites continuously occurred during the drying process together with the removal of water and the increase of the density.

Scavenging property of three cresol isomers against H2O2, hypochlorite, superoxide and hydroxyl radicals

Formocresol has long been used for pulpotomy of primary teeth and as an intracanal medicament. Little is known, however, about the pharmacological effect of tricresols. This study showed that three cresol isomers, o-cresol, m-cresol and p-cresol, are H2O2 scavengers with a 50% inhibitory concentration (IC50) of 502, 6.7 and 10.16 microM, respectively. o-, m- and p-cresol were also shown to be effective scavengers of superoxide radicals generated by xanthine/xanthine oxidase with an IC50 of 282, 153 and > 4000 microM, respectively, as analyzed by luminometer. o-, m- and p-cresol showed protective effects on the DNA breaks generated by H2O2/FeCl2 and FeCl3/ascorbate/H2O2 systems at concentrations ranging from 70 microM to 1.43 mM, o-, m- and p-cresol also showed differential protective effects against DNA breaks induced by 0.17% NaOCl with 100% inhibitory concentration (IC100) of about 10, 1 and 10 mM, respectively. In addition, reaction with 3% H2O2 and 0.17% NaOCl completely prevented NaOCl-induced DNA breaks. The results indicate that the three cresol isomers are effective ROS scavengers and may prevent ROS induced damage when used as pulpotomy agents or as intracanal medicaments. Owing to the difference in the position of the functional hydroxyl group in the three cresol isomers, m-cresol is the most effective ROS scavenger. Concomitant use of H2O2 for root canal irrigation may diminish both the tissue dissolving capacity of NaOCl and NaOCl-induced DNA damage.

Prevention of the areca nut extract-induced unscheduled DNA synthesis of gingival keratinocytes by vitamin C and thiol compounds

There are about 600 million betel quid (BQ) chewers in the world. BQ chewing is the major risk factor of oral cancer in India, Taiwan, South Africa and numerous other countries. Areca nut (AN) extract, the main component of BQ, exerts cytotoxicity and genotoxicity to several types of cells. In the present study, AN extract induced the unscheduled DNA synthesis (UDS) of gingival keratinocytes (GK). Vitamin C, at concentration of 50 and 200 microg/ml prevented the AN-induced UDS by 41 and 56%, respectively. Glutathione (GSH, 1-3 mM) and N-acetyl-L-cysteine (NAC, 1-3 mM) also protected the AN-induced UDS by 89-100 and 76-90%. These preventive effects were not due to cytotoxicity as analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Deferoxamine (20 and 30 mM), an iron chelator and a free radical scavenger, also prevented AN extract induced UDS of GK by 30-55%. On the contrary, banthocuproine (50-200 microM, a copper chelator) and 1,10-phenanthroline (50, 100 microM, a lipid permeable iron chelator), lacked preventive effects. Specific reactive oxygen species scavengers such as dimethyl-sulfoxide (2%), mannitol (10-20 mM), dimethylthiourea (10-20 mM), pyruvate (10 mM), catalase (200 and 400 U/ml), and superoxide dismutase (50 and 200 U/ml) also lacked these preventive effects. Moreover, higher concentrations of H(2)O(2) (0.5-1 mM) inhibited the basal levels of UDS by 19-37%. Interestingly, NAC, GSH, Vitamin C and deferoxamine cannot prevent the AN-induced morphological changes of GK at similar concentrations. These results reveal that AN extract-induced UDS of GK is associated with free radical reactions. Possibly different ingredients of AN is responsible for genotoxicity and cytotoxicity. Vitamin C, GSH and NAC may be potentially used in the future for chemoprevention of BQ chewing related oral mucosal lesions.

Inducing the cell cycle arrest and apoptosis of oral KB carcinoma cells by hydroxychavicol: roles of glutathione and reactive oxygen species

Hydroxychavicol (HC; 10 - 50 microM), a betel leaf component, was found to suppress the 2% H(2)O(2)-induced lucigenin chemiluminescence for 53 - 75%. HC (0.02 - 2 microM) was also able to trap superoxide radicals generated by a xanthine/xanthine oxidase system with 38 - 94% of inhibition. Hydroxyl radicals-induced PUC18 plasmid DNA breaks was prevented by HC (1.6 - 16 microM). A 24-h exposure of KB cells to HC (0.5, 1 mM) resulted in 54 - 74% cell death as analysed by a 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. HC (10, 50 microM) further suppressed the growth of KB cells (15 and 76%, respectively). Long-term colony formation of KB cells was inhibited by 51% with 10 microM HC. Pretreatment of KB cells with 100 microM HC inhibited the attachment of KB cells to type I collagen and fibronectin by 59 and 29%, respectively. Exposure of KB cells to 0.1 mM HC for 24 h resulted in cell cycle arrest at late S and G2/M phase. Increasing the HC concentration to 0.25 and 0.5 mM led to apoptosis as revealed by detection of sub-G(0)/G(1) peaks with a concomitant decrease in the number of cells residing in late S and G(2)/M phase. Inducing the apoptosis of KB cells by HC was accompanied by marked depletion in reduced form of GSH (>0.2 mM) and the increasing of reactive oxygen species production (>0.1 mM) as analysed by CMF- and DCF-single cell fluorescence flow cytometry. These results indicate that HC exerts antioxidant property at low concentration. HC also inhibits the growth, adhesion and cell cycle progression of KB cells, whereas its induction of KB cell apoptosis (HC>0.1 mM) was accompanied by cellular redox changes.