Abstract P2-11-19: Expression of folate receptor alpha in ductal carcinoma in situ of the breast and comparison with that of invasive ductal carcinoma

Background: We have previously shown that the expression of Folate receptor alpha (FRA) is associated with high grade ER-/PR- or triple negative (TN) invasive ductal carcinoma of the breast. The aim of the current study is to investigate the expression pattern of FRA in a cohort of ductal carcinoma in situ (DCIS), analyze its relationship with different clinicopathological features and expression of several key biomarkers, and compare these findings to our previous data on invasive ductal carcinoma (IDC).

Methods: Ninety-eight cases of DCIS of the breast diagnosed between 1997 and 2008 in our institution were identified, reviewed and 6 blocks of tissue microassays (TMA) were constructed. The association between the expression of FRA (≥10% designed as positive expression) and the clinicopathologic features, the expression of ER, PR, HER2 and Ki-67, and the clinical outcome were evaluated, and these results were compared to those from IDC (399/430 cases with informative data). Results: Among the 98 cases of DCIS in TMA, 88 cases were informative. The expression rate of FRA was 21% for DCIS, less than the 29% seen in IDC. Expression of FRA was associated with high nuclear grades (42%), though less frequently than with IDC (52%). FRA expression was also associated with ER negativity (46%), PR negativity (33%) and high Ki-67 expression (50%) in DCIS, although significantly less than in IDC (75%, 63%, and 56%, respectively for negative ER and PR, and high Ki-67). Also, only 50% of ER/PR negative, TN and basal-like DCIS expressed FRA, significantly lower than that of IDC (74%, 80% and 80%, respectively). Due to the limited cases of DCIS, we did not demonstrate a significant difference in disease-free survival between FRA positive and negative tumors (p-value = 0.1792), although we did observe that IDC with FRA expression was significantly associated with a worse disease-free survival (p-value = 0.04).

Comparison between FRA expression between DCIS and IDC FRA≥10% in DCISFRA≥10% in IDCp-value 88 cases399 cases Nuclear 342%52%0.0185ER negative46%75%0.0442PR negative33%63%0.0214HER2 3+31%37%0.7003ER-/PR-50%74%0.0973Triple Negative50%80%0.1622Basal-Like50%80%0.1739

Conclusion: Our data demonstrates that FRA expression is associated with high nuclear grade, ER/PR negative and TN DCIS, though at a significantly lower rate than was observed in IDC, suggesting a possible role for this receptor in early breast carcinogenesis. There are differences in the rates of FRA expression between DCIS and IDC, suggesting that FRA may be one of the key molecules involved in progression of DCIS to IDC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-11-19.

Abstract P2-11-20: Evaluation of folate receptor alpha expression in breast cancer by immunohistochemistry: Analysis with three different cut-off points

Background: Folate receptor alpha (FRA) is a newly recognized molecule that is selectively expressed in certain types of solid tumors, and several targeted therapies against FRA have shown promise in clinical trials for treating FRA-expressing ovarian and lung cancer. FRA has been shown to be selectively expressed in ER/PR negative and triple negative (TN) breast cancer; tumor types which would benefit from FRA targeted therapy. With these FRA-targeted therapies becoming available, correctly identifying eligible patients is very important. Currently, the cut off points for FAR expression by immunochemical (IHC) analysis have not been uniform. The commonly used cut points for expression that have been reported included 5%, 10% and the M score (using both staining intensity (3+, 2+, and 1+) and percentage of cells 0-100% (X, Y, Z for each staining intensity) in the equation (M-score = [3X+2Y+1Z]/ 6). The aim of the current study is to investigate these 3 most frequently used cut off points for FRA IHC analysis, in an effort to identify the one that is the most clinically relevant. Methods: 430 cases of infiltrating ductal carcinoma diagnosed between 1997 and 2008 in our institution were identified, reviewed, and 25 blocks of tissue microassays (TMA) were constructed. The association between the expression of FRA by IHC analysis, the clinicopathologic features, expression of ER, PR, HER2 and Ki-67, and the clinical outcome of these tumors were evaluated. Three cut off points (≥5%, ≥10% and M score of ≥10) were compared. 5% and 10% were scored as percent of membrane/cytoplasmic staining of the tumor cells regardless of the staining intensity while the M score takes into consideration both percentage and intensity of the staining of tumor cells.Results: Among the 430 cases studied, 399 cases had informative data from IHC analysis. The positive rates for FRA were 33%, 29% and 17%, respectively, for 5%, 10% and M score 10 as the positive cut off. All three cut off points were associated with significantly higher tumor grades and higher nodal status; they were also associated significantly with ER negativity, PR negativity or high proliferation rates (Ki-67≥15%) (P-values <0.0001 in all), and ER-/PR-, TN, or Basal-like tumors (p-values <0.0001 in all). Also, they were all significantly associated with worse disease-free survival with the p-values of 0.027, 0.026, and 0.009, for 5%, 10% and M score 10, respectively.

FRA positive rates with three different cut off points FRA ≥5% (%)FRA ≥10% (%)FRA M-score ≥10 (%)Age >50 (year)32%28%17%Tumor size <2 (cm)28%26%16%Histologic grade 351%47%32%LN status >041%34%20%ER negative77%74%56%PR negative66%63%46%HER2 3+48%37%26%Ki67>15%60%56%41%ER-/PR-77%74%54%Triple Negative82%80%60%Basal-like82%80%59%

Conclusion: Our data demonstrates that all three cut off points (5%, 10% and M score 10) could effectively separate breast tumors into subgroups where FRA expression correlated with specific pathologic features and a worse disease-free survival compared with FRA negative tumors. Using an M score of >10 as the cut off for FRA may be most specific method for determining the prognostic significance of FRA expression in breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-11-20.

HER2 status in gastric cancers: a retrospective analysis from four Chinese representative clinical centers and assessment of its prognostic significance

BACKGROUND

HER2 has a predictive value in gastric cancer. However, its association with prognosis remains uncertain. The aim of our study was to estimate the HER2-positive rate in Chinese gastric cancers, compare the classical fluorescence in situ hybridization (FISH) method with the novel bright-field dual color silver-enhanced in situ hybridization (DSISH) detection system, and evaluate the relationship between the HER2 status and prognosis.

PATIENTS AND METHODS

Seven hundred and twenty-six resected gastric cancers separately from four clinical centers in China were examined for HER2 by immunohistochemistry (IHC), FISH, and DSISH.

RESULTS

The HER2-positive rate was 13%. The consistency between FISH and DSISH results was high (99%; κ = 0.958; P < 0.001). Tumor heterogeneity and polysomy were the main reasons for inconsistency. There was no significant difference in the 3-year overall survival (OS) between HER2-positive and -negative patients (P = 0.959). Multivariate analysis showed that HER2 was not an independent prognostic factor.

CONCLUSION(S)

HER2 overexpression and amplification occur in a significant number of Chinese gastric cancer patients. Given the obvious advantages and high consistency with FISH, DSISH was superior for evaluating HER2 amplification in gastric cancer. HER2 was not a prognostic factor for gastric cancer in our study.

HER2 status in gastric cancers: a retrospective analysis from four Chinese representative clinical centers and assessment of its prognostic significance

BACKGROUND

HER2 has a predictive value in gastric cancer. However, its association with prognosis remains uncertain. The aim of our study was to estimate the HER2-positive rate in Chinese gastric cancers, compare the classical fluorescence in situ hybridization (FISH) method with the novel bright-field dual color silver-enhanced in situ hybridization (DSISH) detection system, and evaluate the relationship between the HER2 status and prognosis.

PATIENTS AND METHODS

Seven hundred and twenty-six resected gastric cancers separately from four clinical centers in China were examined for HER2 by immunohistochemistry (IHC), FISH, and DSISH.

RESULTS

The HER2-positive rate was 13%. The consistency between FISH and DSISH results was high (99%; κ = 0.958; P < 0.001). Tumor heterogeneity and polysomy were the main reasons for inconsistency. There was no significant difference in the 3-year overall survival (OS) between HER2-positive and -negative patients (P = 0.959). Multivariate analysis showed that HER2 was not an independent prognostic factor.

CONCLUSION(S)

HER2 overexpression and amplification occur in a significant number of Chinese gastric cancer patients. Given the obvious advantages and high consistency with FISH, DSISH was superior for evaluating HER2 amplification in gastric cancer. HER2 was not a prognostic factor for gastric cancer in our study.

Molecular characterization of long terminal repeat of porcine endogenous retroviruses in Chinese pigs

Pigs offer an unlimited source of xenografts for humans. However, vertically transmitted Porcine endogenous retrovirus (PERV) poses an infectious risk in the course of pig-to-human transplantation. In this study, we characterized PERV long terminal repeat (LTR) sequences from three species of Chinese pigs Banna minipig inbred (BMI), Wu-Zhi-Shan pig (WZSP), and Neijiang pig (NJP-A), and compared them with those of known PERVs (PERV-A, PERV-B, PERV-C, PERV-NIH, and 293-PERV-43). Genomic DNA extracted from peripheral blood mononuclear cells (PBMCs) of the Chinese pigs was used for PCR-amplification, cloning, and sequencing of LTRs. The sequences of BMI and WZSP LTRs were found identical with those of PERV-A and PERV-B, while that of NJP-A LTR was found close to those of PERV-C and PERV-NIH. The gammaretroviral nature of PERV LTRs from Chinese pigs was proved. These LTRs contained also promoter elements including enhancer-like repeats comparable with those of other PERVs. These findings suggested that PERVs from Chinese pigs were similar to PERV-A and PRV-B. Moreover, this study provided new data for the evaluation and selection of pigs to be used in the xenotransplantation.

Studies on long-term infection of human cells with Porcine endogenous retrovirus

A major concern in pig-to-human xenotransplantations is the potential risk of transmission of Porcine endogenous retroviruses (PERVs) integrated in the pig genome. Our previous work has shown that PERV provirus genes and gag protein can be detected in human embryonic kidney HEK-293 cells during a long-term infection with PERV (Yu et al., Transplant. Proc. 37, 496-499, 2005). In this study, we continued studying the long-term (>6 months) PERV infection of HEK-293 cells. The results showed no significant differences in morphology, growth, apoptosis, and [(3)H]-thymidine incorporation between PERV-infected and uninfected cells. The PERV LTR sequence showed only an insignifcant mutation after the long-term infection. PERV infection had no effect on the transcription of genes of Human endogenous retrovirus (HERV) naturally occurring in HEK-293 cells. Summing up, this study indicated that a long-term PERV infection of HEK-293 cells in vitro does not result in any significant changes in host cells as well as in PERV LTR sequence.

Genotype <21CAs/≥21CAs and allele <21CAs of the MANBA gene in melanoma risk and progression in a Swedish population

Cutaneous melanoma is characterized by poor patient outcome in its later stages. The search for genetic markers is therefore crucial for the identification of populations at risk for melanoma. Highly polymorphic CA repeats in 3' proximity in the MANBA gene were examined by PCR-capillary electrophoresis in 185 Swedish melanoma patients and 441 tumor-free age- and gender-matched individuals. The associations of the polymorphisms with melanoma risk, the pigment phenotypes of the patients and tumor characteristics were analyzed. A significant difference in allelic distribution between melanoma patients and tumor-free individuals was observed. The frequency of the MANBA genotype <21CAs/≥21CAs was significantly higher in melanoma patients than in the controls. When comparing allele distribution in patients and their matched controls, the allele <21CAs was found to be associated with the female gender (39.8 vs. 31.2%, P=0.041, OR=1.46, 95% CI 1.02-2.10), but not with male gender (34.4 vs. 30.9%, P%0.39). Within the melanoma group, there were no differences in the distribution of the MANBA alleles associated with patient gender or age before or after 55 years at diagnosis, nor was there any association between the MANBA genotype and pigment phenotype or tumor sites. The MANBA allele <21CAs was, however, associated with thin melanomas at diagnosis (Breslow thickness ≤1.5 mm and Clark levels I and II). In conclusion, these data suggest that MANBA polymorphisms might be an indicator of tumor growth and progression and, together with other markers, could be used to identify individuals at increased risk of melanoma.

Transmission of porcine endogenous retrovirus to human cells in nude mouse

Xenotransplantation is associated with the risk of Porcine endogenous retrovirus (PERV) transmission, since it has been shown that PERV can infect human cells in vitro (Specke et al., Virology 285, 177-180, 2001). We evaluated the possibility of PERV infection of human cells in nude mice model. Porcine kidney cells PK15 carrying PERV and human liver cancer cells SMMC-7721 were injected separately into the right and left axilla of nude mice, respectively. Two months later, pig cytochrome oxidase II (COII) gene, PERV DNA, PERV mRNA, and PERV-Gag protein were detected in the mass formed in both axillas and in several organs of nude mice. The pig COII genes were detected in the right and left axilla, but not in other organs of nude mice implicating that the microchimerism of pig cells occurred in human SMMC-7721 cells and induced the formation of the mass. PERV gene and gag protein were detected in all mouse tissues except liver. These data indicated that (i) PERV may be transmitted from porcine to mouse cells, (ii) PERV genes and proteins were detectable in the mass formed by injection of human cells and consequently (iii) there was a possibility of PERV transmission to human cells after xenotransplantation.

Prevention of glutamate excitotoxicity in motor neurons by 5,6-dihydrocyclopenta-1,2-dithiole-3-thione: implication to the development of neuroprotective drugs

Glutamate-induced excitotoxicity and oxidative damage are believed to play an important role in the development of a number of central nerve system disorders. Nuclear-factor erythroid 2-related factor 2 (Nrf2) is a master transcriptional regulator of many cytoprotective genes. We report herein that 5,6-dihydrocyclopenta-1,2-dithiole-3-thione (CPDT), which was previously shown to induce several Nrf2 target genes in non-nervous cells and tissues, significantly activates Nrf2 and Nrf2 target genes in rat spinal cord explants. More importantly, such activation is accompanied by complete inhibition of glutamate-induced motor neuron death in these explants. Further studies show that CPDT inhibits glutamate-induced intracellular Ca(2+) rise, loss of mitochondrial transmembrane potential and depletion of tissue glutathione. CPDT did not appear to modulate glutamate transport or to interfere with glutamate interaction with postsynaptic receptors. Taken together, our studies have identified CPDT as a promising neuroprotective agent and suggest that pharmacological activation of Nrf2 signaling is an important strategy for protection against glutamate-induced excitotoxicity.

Significance of glutathione S-transferases M1, T1 and P1 polymorphisms in Swedish melanoma patients

Polymorphisms of GSTM1, GSTT1 and GSTP1 were examined in melanoma patients and tumor-free individuals. Relationships between the polymorphisms and tumor characteristics and pigment phenotypes of the patients were analyzed. There was no significant difference in GSTM1 null and GSTT1 null genotypes nor GSTP1 GG genotype between melanoma patients and controls. In melanoma patients, these polymorphisms were not correlated with early or later onset of melanomas or gender of the patients. Frequency of GSTM1 null genotype was higher in patients with melanoma >2.5 mm than in those with tumors <1.0 mm, and higher frequency was found in nodular melanoma than in the other tumor types. GSTP1 GG genotype was more often found in the patients with brown and mixed eye color or brown and black hair than those with blue and green eyes or blond hair. It is unlikely that polymorphisms of GSTM1, GSTT1 and GSTP1 are general risk factors for melanoma in the Swedish population. GSTM1 null genotype was correlated with Breslow thickness and tumor type, which might serve as an additional biomarker for a rapid tumor progression. GSTP1 GG increases risk for melanoma in the subgroup of individuals with dark eyes or hair.

The C-terminal peptide of connective tissue growth factor blocks the full molecule binding to tubular epithelial cell

OBJECTIVES

Interstitial fibrosis is a critical pathologic change in chronic allograft nephropathy. The cytokine connective tissue growth factor (CTGF, also CCN2) plays an important role in epithelial-mesenchymal transformation (EMT) of tubular epithelial cells to renal interstitial fibrosis. The hexadeca-peptide within the C-terminal of CTGF (named P2) contains the unique binding domain of CTGF to its potential receptor, integrin alphavbeta3. This study examined whether P2 bound preferentially to the receptor and served as an inhibitor of CTGF.

METHODS

All studies used an established rat kidney tubular epithelial cell line NRK-52E. Chemically synthesized P2 was purified, and some of it labeled with FITC. The affinity of CTGF or P2 to NRK-52E cells was examined by a solid-phase cell adhesion assay. Competitive binding between P2 and CTGF to NRK-52E cells was examined with flow cytometric analysis.

RESULTS

Both P2 and CTGF bound to the NRK-52E cells, mediating cell adhesion. When the cells were incubated in the mixture of P2 and CTGF, P2 bound to the cells preferentially. Furthermore, when cells were preincubated with excessive CTGF, it became difficult for subsequent P2 binding to occur.

CONCLUSIONS

P2 and CTGF seemed to bind to cell membranes at the same binding domain. P2 competitively blocked CTGF binding, acting as a CTGF inhibitor.

Interference of cyclosporine on glucose metabolism: potential role in chronic transplantation kidney fibrosis

OBJECTIVES

To explore the fibrosis induction effects of cyclosporine (CsA) on renal tubular epithelial cells, as well as the potential mechanisms of CsA-mediated alterations of glucose metabolism in chronic allograft nephropathy (CAN).

METHODS

The rat renal tubular epithelial cell line NRK-52E cells were cultured in medium with 50 mmol/L of D-glucose for 7, 14, or 28 days. The expression of TGF-beta1, CTGF, Smad3, and Smad7, which are involved in the fibrosis signal pathway, was detected by immunofluorescence and reverse-transcriptase polymerase chain reaction. Meanwhile, cells were cultured in various concentration of CsA in glucose-free medium for 24 hours followed by the addition of D-[3-(3)H]-glucose for 30 minutes; glucose uptake was detected by examining the radiation intensity.

RESULTS

The expression of TGF-beta1, Smad3, Smad7, and CTGF of NRK-52E cells were up-regulated significantly (P < .05) after culture with 50 mmol/L glucose for 7 days compared with those in 25 mmol/L glucose. At 14 and 28 days, TGF-beta1 was slightly decreased compared with 7 days, but CTGF, Smad3, and Smad7 increased robustly (P < .05). CsA significantly stimulated glucose uptake at various concentrations, with an absorption peak at 60 minutes that decreased at 75 minutes. Furthermore, CsA may have dose-dependent effects on glucose uptake.

CONCLUSION

High glucose concentrations may play an important role in the NRK-52E cell fibrosis during the CAN process due to an interference of CsA on glucose metabolism.

Nuclear Translocation of SMAD3 May Enhance the TGF-β/SMADS Pathway in High Glucose Circumstances

OBJECTIVES

Posttransplant diabetes mellitus is one of the most frequent complications after kidney transplantation. It is considered to be one cause of chronic allograft nephropathy. This study sought to investigate the effects of high glucose on the expression and nuclear translocation of Smad3, which is an important signal mediator involved in the fibrotic signal pathway.

METHODS

The established rat renal mesangial cell line HBZY-1 was cultured in medium with various concentrations of glucose (4.5 mg/mL, 9.0 mg/mL, or 13.5 mg/mL), which was collected at 7, 14, or 21 days. The total expression of Smad3, including both inner and outer nucleus proteins was examined by Western blot analysis. The nuclear translocated Smad3, representing only the inner nucleus protein, was detected by immunofluorescence staining observed under a laser confocal scanning microscope.

RESULTS

No significant difference in the total Smad3 expression was demonstrated by Western blot analysis among the three groups of HBZY-1 cells at various concentration of glucose after 7, 14, or 21 days. There was no fluorescence detected in the nucleus at day 7 by immunofluorescence staining; however, robust positive expression of Smad3 was detected at days 14 and 21.

CONCLUSION

As a restricted Smads member, Smad3 protein might not be upregulated in the presence of high glucose. However, with prolonged culture time, Smad3 translocates from cytoplasm to nucleus, which may be a pivotal step in the fibrotic signal pathway.