Breast Cancer Index and prediction of benefit from extended endocrine therapy in breast cancer patients treated in the Adjuvant Tamoxifen-To Offer More? (aTTom) trial

BACKGROUND

Extending the duration of adjuvant endocrine therapy reduces the risk of recurrence in a subset of women with early-stage hormone receptor-positive (HR+) breast cancer. Validated predictive biomarkers of endocrine response could significantly improve patient selection for extended therapy. Breast cancer index (BCI) [HOXB13/IL17BR ratio (H/I)] was evaluated for its ability to predict benefit from extended endocrine therapy in patients previously randomized in the Adjuvant Tamoxifen-To Offer More? (aTTom) trial.

PATIENTS AND METHODS

Trans-aTTom is a multi-institutional, prospective-retrospective study in patients with available formalin-fixed paraffin-embedded primary tumor blocks. BCI testing and central determination of estrogen receptor (ER) and progesterone receptor (PR) status by immunohistochemistry were carried out blinded to clinical outcome. Survival endpoints were evaluated using Kaplan-Meier analysis and Cox regression with recurrence-free interval (RFI) as the primary endpoint. Interaction between extended endocrine therapy and BCI (H/I) was assessed using the likelihood ratio test.

RESULTS

Of 583 HR+, N+ patients analyzed, 49% classified as BCI (H/I)-High derived a significant benefit from 10 versus 5 years of tamoxifen treatment [hazard ratio (HR): 0.35; 95% confidence interval (CI) 0.15-0.86; 10.2% absolute risk reduction based on RFI, P = 0.027]. BCI (H/I)-low patients showed no significant benefit from extended endocrine therapy (HR: 1.07; 95% CI 0.69-1.65; -0.2% absolute risk reduction; P = 0.768). Continuous BCI (H/I) levels predicted the magnitude of benefit from extended tamoxifen, whereas centralized ER and PR did not. Interaction between extended tamoxifen treatment and BCI (H/I) was statistically significant (P = 0.012), adjusting for clinicopathological factors.

CONCLUSION

BCI by high H/I expression was predictive of endocrine response and identified a subset of HR+, N+ patients with significant benefit from 10 versus 5 years of tamoxifen therapy. These data provide further validation, consistent with previous MA.17 data, establishing level 1B evidence for BCI as a predictive biomarker of benefit from extended endocrine therapy.

TRIAL REGISTRATION

ISRCTN17222211; NCT00003678.

Abstract P1-15-03: Management and outcomes of metaplastic breast cancer

Purpose/Objectives: Metaplastic breast cancer (MBC) is a rare malignancy composed of both epithelial and mesenchymal components that accounts for less than 1% of primary breast carcinomas. Knowledge of effective management of the disease remains limited. We retrospectively evaluated the treatment and outcomes of patients with MBC from three academic hospitals.

Materials/Methods: Patients diagnosed with MBC between June 2, 1993 and May 6, 2016 were identified. Demographic and clinical variables were extracted via primary chart review. Descriptive statistics were utilized to summarize the patient cohort's clinical course. The Kaplan-Meier method was used to obtain estimates of local control (LC) and survival.

Results: Seventy-six patients were identified with a median follow-up of 7.6 years (range: 0.18-19.9 years). The median age at diagnosis was 54 (range 28-81). About two-thirds of patients (67%, n=51) presented with a palpable mass while the remaining patients were screen-detected via mammogram (32%, n=24). The majority of patients were AJCC-7 stage I (38%, n=29) or stage II (49%, n=37), while 10% (n=8) were stage III and 3% (n= 2) stage IV. About half of tumors (46%, n=35) were subtyped using WHO histologic classification of MBC. Over half of subtyped cases were spindle cell carcinoma (51%, n=18), 17% were matrix-producing carcinoma (n=6), 23% were adenocarcinoma with squamous differentiation (n=8), 6% were carcinosarcoma (n=2), and 3% were mixed (n=1).The majority of patients had triple negative disease (82%, n=62), while 13% (n=10) had HR+/HER2- disease, and 5% (n=4) had HER2+ disease. Most patients had high grade tumors (84%, n=64) and received breast conserving surgery (61%, n=46) while 39% (n=29) had mastectomies. Seventy-six percent (n=58) of patients received chemotherapy and 61% (n=46) received radiation therapy. All HR+ patients received adjuvant endocrine therapy, and 1 patient received immunotherapy. Of patients who received chemotherapy, 78% (n=45) received adjuvant therapy alone, 17% (n=10) neoadjuvant therapy alone, and 5% (n=3) both. Seventy percent (n=41) of chemotherapy regimens included a taxane. Among 74 patients without metastatic disease at presentation, recurrences were observed in 18% (n=13). Most patients recurred distantly (69%, n=9), while the remainder had isolated local recurrences (n=4). Of 9 distant failures, 3 had MBC subtype information and all 3 were spindle cell carcinoma. Of 4 local recurrences, 3 of 4 were adenocarcinoma with squamous cell differentiation and 1 was spindle cell carcinoma. At a median follow-up of 7.6 years, the local recurrence-free survival was 88%, disease-free survival was 80%, and overall survival was 80%. Kaplan-Meier point estimates for remaining free of local recurrence versus distant recurrence were 99% (95% C.I., 90- 100) versus 96% (95% C.I., 87- 99) at 2 years and 88% (95% C.I., 76-94) versus 87% (95% C.I., 75- 93) at 5 years.

Conclusions: MBC is a rare histologic subtype that commonly presents with high-grade disease and triple-negative receptor status. In contrast to other smaller series, local and distant failure rates in this cohort were consistent with non-MBC triple negative cohorts. Additional molecular based research is warranted to further characterize features associated with local and distant failure.

Citation Format: Thomas H, Horick N, Spring LM, Brachtel EF, Jimenez RB. Management and outcomes of metaplastic breast cancer [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 P1-15-03.

Abstract P2-12-05: Real-time, intraoperative detection of residual breast cancer in lumpectomy cavity margins using the LUM imaging system: Results of a feasibility study

Background: Obtaining tumor-free margins is critical for local control in breast conserving surgery. Currently, 20-40% of lumpectomy patients have positive margins that require surgical re-excision. We assessed the LUM Imaging System for real-time, intraoperative detection of residual tumor in breast cancer patients. The LUM System has the particular advantage of assessing in vivo lumpectomy cavity walls rather than excised specimens, to enable more accurate excision of residual tumor.

Methods: Lumpectomy cavity walls of patients undergoing lumpectomy for invasive breast cancer or ductal carcinoma in situ (DCIS), were assessed intraoperatively using the LUM Imaging System (Lumicell Inc., Wellesley MA). LUM015, a cathepsin-activatable fluorescent agent, was given IV 4±2 hrs prior to surgery. Areas of fluorescence generated at potential sites of residual tumor in lumpectomy cavities were evaluated with a sterile hand-held device, displayed on a monitor, excised and correlated with histopathology.

Results: In vivo lumpectomy cavities were imaged with the LUM Imaging System in 60 breast cancer patients. 5 were imaged without dye. 55 received LUM015 dye preoperatively and were scanned intraoperatively. Median age was 60 years (range 44-79). Mean tumor size was 1.2cm (0.06-3.5cm) with 71% invasive cancers, 29% DCIS. The test set included 569 cavity margin surfaces assessed intraoperatively and excised. Image acquisition for each margin took approximately 1 second. The LUM Imaging System showed 100% sensitivity and 73% specificity for detection of tumor <2mm from the margin. Invasive ductal cancer (IDC), invasive lobular cancer (ILC) and areas of DCIS 1mm in size could be identified. 8 patients had positive margins on standard histopathology analysis (Table). The LUM System correctly identified all positive margins identified by standard histopathology and correctly predicted negative re-excisions in 2 of 8 patients. There were no serious adverse events. 1 patient had extravasation of LUM015 at her injection site with temporary blue skin staining but no other complication.

Conclusions: The LUM Imaging System allows real-time identification of residual tumor in the lumpectomy cavity of breast cancer patients. No sites of residual tumor were missed. Additional studies are underway to optimize this approach for reducing positive margins and second surgeries in breast cancer patients.

Table: Margin results in 8 patients with positive margins on initial lumpectomy specimenPositive lumpectomy margin histopathologyLUM cavity wall result (+/- for tumor)Tumor found at re-excisionDCIS++DCIS+-DCIS++IDC++ (Mastectomy)ILC++ (Mastectomy)DCIS+-IDC--DCIS--

Citation Format: Lanahan CR, Gadd MA, Specht MC, Ferrer J, Tang R, Rai U, Merrill AL, Biernacka A, Brachtel E, Smith BL. Real-time, intraoperative detection of residual breast cancer in lumpectomy cavity margins using the LUM imaging system: Results of a feasibility study [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 P2-12-05.

Abstract P1-06-03: Serial evolution of hormone receptor status and mutational profile among patients with metastatic breast cancer

Introduction: Tumor heterogeneity presents a significant impediment to identifying appropriate treatments for patients. Genetic mutations and hormone receptors are frequently used as a guide for selecting appropriate targeted or hormonal therapies, however it is possible that these markers may change over time, leading to reduced effectiveness of these treatments. In this study, we review the results of serial and paired biopsies to identify receptor switch in estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status as well as to identify changes in clinically relevant mutations, including spatial and temporal heterogeneity.

Methods: We identified a total of 237 patients initially presenting with ER+/HER2 negative breast cancer and who had multiple biopsies during the course of their treatment, including at least one in the metastatic setting. ER, PR, and HER2 status for each of these serial biopsies was gathered from chart reviews. HER2 results by both IHC and FISH were collected. PIK3CA mutations were also assessed by Snapshot utilizing multiplexed PCR of common hotspot mutations using DNA derived from formalin-fixed, paraffin-embedded (FFPE) tissue.

Results: From a total of 213 patients with known ER status for multiple serial biopsies, we identified 9.4% (N=20) who had at least one change in ER status over time. From a total of 198 patients who had documented PR status for multiple biopsies, 40.4% (N=80) had at least one change in PR status. Changes in HER2 status were similarly assessed, with 6.7% of patients having at least one change by IHC and 4.4% of patients having at least one change by FISH. Of those patients exhibiting changes in ER status, 6 were noted to have multiple changes over time. Of those with changes in PR status, 18 had multiple changes over time. Changes in hormone receptor status were also noted to occur between serial biopsies in the metastatic setting. A total of 128 patients had ER results available for multiple metastatic specimens, of which 8.6% (N=11) had at least one change in ER status. A total of 116 patients had PR results available for multiple metastatic biopsies, of which 38.8% (N=45) had at least one change in PR status. Changes were also noted in the metastatic setting in HER2 (IHC) with a frequency of 8.7% and in HER2 (FISH) with a frequency of 4.7%. A subset of 108 patients were identified as harboring a mutation in PIK3CA. Within this population, 9.6% of patients had at least one change in ER status over time and 34.1% had at least one change in PR status. 9.0% exhibited at least one change in HER2 (IHC) and 6.5% in HER2 (FISH). Serial changes in genotype, from pre- and post-treatment biopsies, were also detected using NGS based Foundation Medicine platform, including acquired alterations in the ESR1 and PI3K pathway.

Conclusion: Serial changes in hormone receptor status and mutation profile are not uncommon among patients initially diagnosed with ER+/HER2 negative breast cancer, and some patients have been noted to have multiple changes over time. Further studies are needed to understand the mechanistic underpinnings governing the emergence of these alterations and their relationship to therapeutic resistance in breast cancer.

Citation Format: Henderson L, Brachtel E, Fitzgerald D, Gadd M, Specht M, Thabet A, Gurski J, Sgroi D, Moy B, Isakoff S, Bardia A, Juric D. Serial evolution of hormone receptor status and mutational profile among patients with metastatic 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 P1-06-03.

Abstract P4-01-05: In vivo, intraoperative margin detection utilizing the Lumicell margin assessment system

This abstract was withdrawn by the authors.

Abstract P5-03-01: An optimized 92-gene assay for the molecular diagnosis of triple-negative breast cancer

Background: Triple negative breast cancer (TNBC) often presents as high grade, poorly differentiated tumors resulting in a more aggressive disease for which accurate and timely diagnosis is critical to treatment selection or clinical trial enrollment. Furthermore, the high rate of distant metastases and absence of breast-specific immunohistochemical markers that contribute to diagnostic uncertainty may delay or limit treatment modalities that can lead to poorer outcomes. The 92-gene assay is an RT-PCR-based cancer classifier that previously demonstrated 80% accuracy for the diagnosis of breast cancer. In this study, blinded validation of an optimized algorithm and assay specifically developed to improve performance in TNBC is described.

Methods: To increase clinical scope for the diagnosis of TNBC, formalin fixed paraffin embedded specimens (N=103) representing a range of breast tumor histologies (e.g. TNBC, adenoid cystic, neuroendocrine, metaplastic, lobular, mucinous, DCIS) were added to the tumor reference database. A revised computational algorithm was constructed by the integration of machine learning techniques. For validation, tumor specimens (N=160) of TNBC (57%) and non-breast tumors (43%) were blindly tested using a 92-gene cancer classifier (CancerTYPE ID®, Biotheranostics, Inc). Tumor type predictions were reported as rank-order probabilities based on the degree of similarity to the tumor reference database. Assay sensitivity based on concordance of the main tumor type prediction with the reference diagnosis established by clinicopathologic review was analyzed.

Results: Assay results included 85 breast carcinomas (TNBC) (53%), 23 Salivary gland carcinomas (14%), and 52 carcinomas (33%) representing 11 other tumor types. For performance in TNBC, the 92-gene assay demonstrated an overall sensitivity of 93% (CI, 86-98), and sensitivities of 96% [95% CI, 89-99] and 80% [95% CI, 52-96], in primary and metastatic tumors, respectively (P=0.085). Additional performance characteristics are shown in Table 1.

Table 1Pathology subsetN, Validation setN, Correct 92-gene assay predictionsSensitivity (95% CI)All TNBC91850.93 (0.86-0.98)TNBC-primary76730.96 (0.89-0.99)TNBC-metastatic15120.80 (0.52-0.96)All Non-breast69550.80 (0.68-0.88)Salivary gland carcinoma25230.92 (0.74-0.99)Overall performance1601400.88 (0.81-0.92)

Conclusions: An optimized 92-gene assay specifically modified to increase performance for the molecular diagnosis of TNBC showed strong accuracy in this blinded study. These findings support use of the 92-gene cancer classifier to aid in the diagnosis of primary or metastatic TNBC. With more refined tumor characterization, TNBC-specific chemotherapy regimens or clinical trial therapies may be pursued with the potential for improved patient outcomes.

Citation Format: Sullivan PS, Soifer HS, Liu J, Zhang Y, Schnabel CA, Brachtel EF. An optimized 92-gene assay for the molecular diagnosis of triple-negative 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 P5-03-01.

Abstract P2-01-14: circulating tumor cells in breast cancer exhibit dynamic changes in epithelial and mesenchymal cell composition

Epithelial to mesenchymal transition (EMT) has been postulated to contribute to the migration and dissemination of cancer cells, but supporting histopathological evidence is limited. We used a microfluidic device to isolate circulating tumor cells (CTCs), combined with multiplex fluorescent RNA-in-situ hybridization (ISH) and RNA sequencing, to quantify and characterize EMT in breast cancer cells within the bloodstream. Whereas only rare (0.1–10%) cells in the primary tumor expressed both mesenchymal and epithelial markers, such biphenotypic as well as purely mesenchymal cells were enriched among CTCs, across all histological subtypes of breast cancer. Analysis of the therapy response in 8 patients suggest an association of mesenchymal CTCs with disease progression. In an index patient followed longitudinally, fluctuation in epithelial and mesenchymal states was observed as a function of initial response and subsequent resistance to therapy. Mesenchymal markers were predominant in clusters of tumor cells, many of which had adherent platelets. Finally, RNA sequencing of mesenchymal CTC clusters identified TGF-B and other EMT-related signatures, which were absent from more epithelial CTCs. FOXC1, a known regulator of EMT, was abundantly expressed in mesenchymal CTCs and was detectable within localized regions of the primary breast tumor. Together, these data support a role for EMT in the blood-borne dissemination of breast cancer and point to the dynamic nature of this cell fate change.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-01-14.

P4-11-12: Molecular Phenotype of Breast Cancers in a Large Cohort of Young Women According to Time Interval Since Pregnancy

Background: The increase in breast cancer risk during pregnancy and post partum is well recognized. The cross-over to protective effect does not occur until many years later and varies with age at first birth. Recently, a genomic signature specific to the pregnant compared with the non-pregnant breast has been identified; this signature remains present in the postmenopausal parous breast. Given this, we investigated whether time interval since pregnancy affects the phenotype of breast cancers arising in young women compared with nulliparous women. Methods: We examined molecular phenotype, according to histologic grade and biomarker status, in relation to time since pregnancy in an ongoing prospective cohort study (n=355) of young women (≤40yrs) with breast cancer. Medical records were reviewed for tumor stage and receptor status. Parity was ascertained from questionnaires completed within 9 months of diagnosis. Tumor grade was determined by central pathology review. Using tumor grade and biomarker expression, cancers were categorized as luminal A (ER+ and/or PR+, HER2−, histologic grade 1 or 2); luminal B ( ER+ and/or PR+, HER2+, or ER and/or PR+, HER2− and grade 3); HER2 type (ER-, PR-, HER2+); and triple negative (ER-, PR-, HER2−).

Results: The median age of the study population is 37 years (range 17–40). Overall, 80% of women had stage 1 or 2 disease; 67% of cancers were ER positive and 32% showed HER2 overexpression. The distribution of breast cancer molecular phenotypes by time interval since last pregnancy is shown in the table.

Distribution of molecular phenotype by interval between last pregnancy and diagnosis

Pathologic features and molecular phenotype by patient age in a large cohort of young women with breast cancer

Prior studies have suggested a higher prevalence of high grade, ER-negative, HER2-positive, and basal-like carcinomas in young women with breast cancer. However, the precise distribution of poor prognostic features in this population remains unclear. We examined the pathologic features and distribution of molecular phenotype in relation to patient age in a large group of young women (≤40 years) with invasive breast cancer. Medical records were reviewed for clinical characteristics, tumor stage, and receptor status. Pathologic features, including those features associated with basal-like carcinomas, were examined by central review. Using tumor grade and biomarker expression, cancers were categorized as luminal A (ER+ and/or PR+ and HER2-, histologic grade 1 or 2); luminal B (ER+ and/or PR+ and HER2+, or ER and/or PR+, HER2- and grade 3); HER2 (ER and PR- and HER2+); and triple negative (ER-, PR-, and HER2-). Among 399 women of ≤40 years, 33% had luminal A tumors, 35% luminal B, 11% HER2 (ER-negative), and 21% triple negative. Compared to published results for all breast cancers, a greater proportion of young women had luminal B tumors, and a lesser proportion had luminal A. There were no significant differences in molecular phenotype, tumor stage or grade among the different age groups of young women. However, this population of young women presented with a different distribution of molecular phenotypes compared to the general population of women with breast cancer. These findings may have implications with regard to the etiology and prognosis of breast cancer in young women.

Breast tumor progression induced by loss of BTG2 expression is inhibited by targeted therapy with the ErbB/HER inhibitor lapatinib

The B-cell translocation gene-2 (BTG2), a p53-inducible gene, is suppressed in mammary epithelial cells during gestation and lactation. In human breast cancer, decreased BTG2 expression correlates with high tumor grade and size, p53 status, blood and lymph vessel invasion, local and metastatic recurrence and decrease in overall survival, suggesting that suppression of BTG2 has a critical role in disease progression. To analyze the role of BTG2 in breast cancer progression, BTG2 expression was knocked down in mammary epithelial cells. Suppression of BTG2 enhances the motility of cells in vitro and tumor growth and metastasis in vivo. The effects of BTG2 knockdown are mediated through stabilization of the human epidermal growth factor receptor (HER) ligands neuregulin and epiregulin and activation of the HER2 and HER3 receptors, leading to elevated AKT phosphorylation. Suppression of HER activation using the tyrosine kinase inhibitor lapatinib abrogates the effects of BTG2 knockdown, including the increased cell migration observed in vitro and the enhancement of tumorigenesis and metastasis in vivo. These results link BTG2-dependent effects on tumor progression to ErbB receptor signaling, and raise the possibility that targeted inhibition of this pathway may be relevant in the treatment of breast cancers that have reduced BTG2 expression.

HOXB9 Promotes the Acquisition of Tumorigenic Phenotypes in Mammary Epithelial Cells

Background:The class I HOX gene family consists of 39 members with a shared highly conserved 61-amino acid homeodomain motif. HOX genes are important regulators of developmental processes, and their role in neoplastic transformation and tumor progression is increasingly recognized (Abate-Shen et al., Nat Rev Cancer, 2002; Cantile et al., Eur J Cancer, 2003). However, the molecular mechanisms by which HOX proteins promote tumorigenesis is not well understood. We recently, observed that HOXB9, a 9th HOX gene paralogue involved in mouse mammay gland development, is deregulated in breast cancer and enhanced expression correlated with high tumor grade. A role for elevated HoxB9 expression in breast tumor progression is demontrated by its ability to activate the ErbB and TGF-B pathways which influence tumor-associated phenotypes in cells.Methods and results:Overexpression of HOXB9 was found in 43% of primary breast cancer by RT-PCR and in situ hybridization (Figure 1A) and correlated with high tumor grade. Ectopic expression of HOXB9 in MCF10A mammary epithelial cells induced EMT, cell migration, invasion (Figure 1B, and 1C). It also increased the expression of angiogenic factors, which enhance the formation of new vessels in mouse dorsal air sac model. Conversely, genetic ablation of endogenous HOXB9 in MDA-MB-231 breast cancer cells suppresses their motility and angiogenic potential. Further, we confirmed that HOXB9-induced tumor phenotypes arise through the activation of both ErbB-AKT and TGFß signaling pathways. Finally, in mouse xenograft model, we observed that HOXB9 cooperates with activated H-Ras to transform mammary epithelial cells leading to large, vascularized and invasive tumors (Figure 2).Discussion:Our findings imply that overexpression of HOXB9 in human breast cancer contributes to tumor progression through activation of signaling pathways that alter both tumor-specific cell fates and tumor-stromal microenvironment, leading to increased invasion and metastasis. It is suggested that combined suppression of ErbB and TGFß signaling pathways to target breast cancers overexpressing HOXB9 may be effective in tumor inhibition.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6145.

Development and validation of a model predictive of occult nipple involvement in women undergoing mastectomy

Background

This prospective study aimed to build a predictive model using preoperative information to aid selection for nipple-sparing mastectomy.

Methods

Two hundred consecutive skin-sparing mastectomy specimens without overt nipple involvement were evaluated. Demographic, preoperative pathology and imaging information was collected. Nipple specimens (2 × 2 × 2 cm) were sectioned at 3-mm intervals. Haematoxylin and eosin-stained slides were examined by a breast pathologist for involvement by tumour. Logistic regression analyses of 65 therapeutic procedures identified factors associated with occult involvement and created a predictive model. This was tested on specimens from a further 65 therapeutic procedures.

Results

Occult nipple involvement was noted in 32 (24·6 per cent) of 130 mastectomy specimens. In the training set, imaging diameter of the lesion and its distance from the nipple predicted nipple involvement on univariable analysis (P = 0·011 and P = 0·014 respectively). The multivariable logistic regression model was validated in the test set. The areas under the receiver–operating characteristic curve were 0·824 and 0·709 for the training and test sets respectively.

Conclusion

Three-quarters of women undergoing mastectomy did not have occult nipple involvement. A clinical tool including tumour size and distance from the nipple has been developed to improve patient selection for nipple-sparing mastectomy.

High frequency of β-catenin mutations in borderline endometrioid tumours of the ovary

Some low-grade endometrioid carcinomas arise from a background of endometrioid tumours of borderline malignancy. To determine the molecular mechanisms involved in the initiation of endometrioid carcinoma, the present study investigated whether the genetic alterations reported in these tumours (mutations in PTEN, KRAS, and beta-catenin genes, and microsatellite instability) are already present in endometrioid tumours of borderline malignancy. Eight endometrioid tumours of borderline malignancy were studied. By immunohistochemistry, beta-catenin was expressed in the nuclei of all tumours, suggesting the presence of stabilizing beta-catenin mutations. By mutational analysis, five different beta-catenin mutations were found in seven of eight cases (90%), affecting codons 32, 33, and 37. In contrast, only one tumour harboured a PTEN mutation, which affected codon 130. Neither KRAS mutations nor microsatellite instability was detected. A review of the literature indicated that beta-catenin mutations are characteristic of well-differentiated endometrioid carcinomas, since they were present in nearly 60% of grade I but in less of 3% of grade III tumours. In conclusion, the present study identifies beta-catenin mutation as a nearly constant molecular alteration in borderline endometrioid tumours, whereas PTEN and KRAS mutations and microsatellite instability are very infrequent. The findings in the present study, and previously reported data, strongly suggest that beta-catenin mutation is an early event in endometrioid ovarian carcinogenesis, and that it is involved in the development of low-grade endometrioid tumours.

Human skin Langerhans cells are targets of dengue virus infection

Dengue virus (DV), an arthropod-borne flavivirus, causes a febrile illness for which there is no antiviral treatment and no vaccine. Macrophages are important in dengue pathogenesis; however, the initial target cell for DV infection remains unknown. As DV is introduced into human skin by mosquitoes of the genus Aedes, we undertook experiments to determine whether human dendritic cells (DCs) were permissive for the growth of DV. Initial experiments demonstrated that blood-derived DCs were 10-fold more permissive for DV infection than were monocytes or macrophages. We confirmed this with human skin DCs (Langerhans cells and dermal/interstitial DCs). Using cadaveric human skin explants, we exposed skin DCs to DV ex vivo. Of the human leukocyte antigen DR-positive DCs that migrated from the skin, emigrants from both dermis and epidermis, 60-80% expressed DV antigens. These observations were supported by histologic findings from the skin rash of a human subject who received an attenuated tetravalent dengue vaccine. Immunohistochemistry of the skin showed CD1a-positive DCs double-labeled with an antibody against DV envelope glycoprotein. These data demonstrate that human skin DCs are permissive for DV infection, and provide a potential mechanism for the transmission of DV into human skin.

[Fistula between the trachea and innominate artery--a rare complication following tracheostenosis treatment with silastic tubes]

BACKGROUND

Fistulas between the trachea and innominate artery are rare but devastating complications that usually occur following tracheotomies.

METHODS

One case a fistula after long-term treatment of a tracheal stenosis with an Montgomery silastic tube was analyzed. A literature review of the different strategies in diagnosis and treatment of this complication was undertaken.

RESULTS

In the present case, the fistula occurred after long-term treatment of tracheal stenosis with silastic tubes (Montgomery). Summarizing our experience with this case and a review of the literature, it can be concluded that: Fistulas most frequently occur following tracheostomy or tracheal reconstructive surgery. Frequent bronchoscopic examination during long-term treatment of tracheal stenosis with silastic tubes is essential. Even minor tracheal hemorrhage in such cases must be thoroughly examined. In case of fistula hemorrhage, the most effective treatment consists of direct local compression, best obtained with a well placed respiration tube.

CONCLUSION

Fistulas between the trachea and innominate artery constitute a rare but possible complication after tracheal stenosis treatment.

Differences in the germinal centres of palatine tonsils and lymph nodes

The germinal centres of human palatine tonsils typically have four clearly recognizable compartments. The dark zone is identified by the presence of centroblasts and a thin follicular dendritic cell (FDC) network. The dense FDC network is divided into a CD23(low/-) portion adjacent to the dark zone (the basal light zone) and a CD23(high) portion, the apical light zone). The outer zone, which lies between the apical light zone and the follicular mantle, has only fine CD23- FDC processes. While these compartments were seen in 48 follicles from eight tonsils, the compartmental structure of 54 germinal centres in lymph nodes from 11 individuals was markedly different. The CD23+ FDC network in lymph node follicles extended into part of the dark zone and the inner part of the follicular mantle, and consequently no outer zone or basal light zone was identified. In both the lymph nodes and tonsils most T cells were CD4+ and located outside the dark zone; the concentration of these cells at the edge of germinal centres was typical of tonsil centres but was noted only occasionally in lymph nodes. The substantial minority of T cells that were CD4,CD57+ were located mainly in the dense FDC network.