Dataset Information

Loss of PTEN in high grade advanced stage triple negative breast ductal cancers in African American women.

ABSTRACT: INTRODUCTION:PTEN is a tumor suppressor gene that inhibits cell proliferation by inhibiting the phosphoinositide 3-kinase (PI3?K) signaling pathway. The significance of PTEN mutations resulting in variable PTEN expression and their impact on prognosis of breast cancer is not well established. The objective of our study was to correlate the immunohistochemical expression of PTEN in the four major subtypes of breast carcinoma (Luminal A, Luminal B, HER2 positive, and Triple Negative) in a population of 202 African-American (AA) females with other clinicopathological factors. MATERIALS AND METHODS:Tissue microarrays (TMAs) were constructed from FFPE tumor blocks from primary ductal breast carcinomas in 202 African-American females. Five micrometer sections were stained with a mouse monoclonal antibody against PTEN. The sections were evaluated for the intensity of cytoplasmic and nuclear reactivity. Bivariate analysis was done via ?2 analysis and survivability data was calculated via the generation of Kaplan-Meier curves (SPSS v19). RESULTS:Loss of PTEN expression was associated with ER negative (p?=?0.021), PR negative (p?=?0.024) and triple negative (p?=?0.0024) breast ductal cancers. It was marginally associated with distant metastasis (p?=?0.074). There was no association between PTEN loss and recurrence-free survival or overall survival. CONCLUSION:In our study, a statistically significant association between PTEN loss and the triple negative breast cancers (TNBC) was found in AA women. PTEN inhibits PI3?K resulting in decreased activation of downstream effector, mammalian target of rapamycin (mTOR). Loss of PTEN results in cell proliferation through activation of mTOR. Targeted therapy with mTOR inhibitors might be useful in the treatment of TNBC.

SUBMITTER: Khan F

PROVIDER: S-EPMC5963715 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Loss of PTEN in high grade advanced stage triple negative breast ductal cancers in African American women.

Khan Farhan F Esnakula Ashwini A Ricks-Santi Luisel J LJ Zafar Rabia R Kanaan Yasmine Y Naab Tammey T

Pathology, research and practice 20180327 5

<h4>Introduction</h4>PTEN is a tumor suppressor gene that inhibits cell proliferation by inhibiting the phosphoinositide 3-kinase (PI3 K) signaling pathway. The significance of PTEN mutations resulting in variable PTEN expression and their impact on prognosis of breast cancer is not well established. The objective of our study was to correlate the immunohistochemical expression of PTEN in the four major subtypes of breast carcinoma (Luminal A, Luminal B, HER2 positive, and Triple Negative) in a ...[more]

PMID: 29653745

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Project description:BACKGROUND: Although diagnosed less often, breast cancer in African American women (AAW) displays different characteristics compared to breast cancer in Caucasian women (CW), including earlier onset, less favorable clinical outcome, and an aggressive tumor phenotype. These disparities may be attributed to differences in socioeconomic factors such as access to health care, lifestyle, including increased frequency of obesity in AAW, and tumor biology, especially the higher frequency of triple negative breast cancer (TNBC) in young AAW. Improved understanding of the etiology and molecular characteristics of TNBC in AAW is critical to determining whether and how TNBC contributes to survival disparities in AAW. METHODS: Demographic, pathological and survival data from AAW (n = 62) and CW (n = 98) with TNBC were analyzed using chi-square analysis, Student's t-tests, and log-rank tests. Frozen tumor specimens were available from 57 of the TNBC patients (n = 23 AAW; n = 34 CW); RNA was isolated after laser microdissection of tumor cells and was hybridized to HG U133A 2.0 microarrays. Data were analyzed using ANOVA with FDR <0.05, >2-fold difference defining significance. RESULTS: The frequency of TNBC compared to all BC was significantly higher in AAW (28%) compared to CW (12%), however, significant survival and pathological differences were not detected between populations. Gene expression analysis revealed the tumors were more similar than different at the molecular level, with only CRYBB2P1, a pseudogene, differentially expressed between populations. Among demographic characteristics, AAW consumed significantly lower amounts of caffeine and alcohol, were less likely to breastfeed and more likely to be obese. CONCLUSIONS: These data suggest that TNBC in AAW is not a unique disease compared to TNBC in CW. Rather, higher frequency of TNBC in AAW may, in part, be attributable to the effects of lifestyle choices. Because these risk factors are modifiable, they provide new opportunities for the development of risk reduction strategies that may decrease mortality by preventing the development of TNBC in AAW.

Project description:PurposeAfrican-American (AA) patients with triple-negative breast cancer (TNBC) are less likely to achieve pathologic complete response from neoadjuvant chemotherapy and have poorer prognosis than Caucasian patients with TNBC, suggesting potential biological differences by race. Immune infiltration is the most consistent predictive marker for chemotherapy response and improved prognosis in TNBC. In this study, we test the hypothesis that the immune microenvironment differs between AA and Caucasian patients.MethodsRNA-seq expression data were obtained from The Cancer Genome Atlas (TCGA) database for 162 AA and 697 Caucasian breast cancers. Estrogen receptor (ER)-positive, human epidermal growth factor receptor-2 (HER2)-positive, and TNBC subtypes were included in the analyses. Tumor infiltrating lymphocyte (TIL) counts, immunomodulatory scores, and molecular subtypes were obtained from prior publications for a subset of the TNBC cases. Differences in immune cell distributions and immune functions, measured through gene expression and TIL counts, as well as neoantigen, somatic mutation, amplification, and deletion loads, were compared by race and tumor subtype.ResultsImmune metagene analysis demonstrated marginal immune attenuation in AA TNBC relative to Caucasian TNBC that did not reach statistical significance. The distributions of immune cell populations, lymphocyte infiltration, molecular subtypes, and genomic aberrations between AA and Caucasian subtypes were also not significantly different. The MHC1 metagene demonstrated increased expression in AA ER-positive cancers relative to Caucasian ER-positive cancers.ConclusionsThis study suggests that the immunological differences between AA and Caucasian breast cancers represented by TCGA data are subtle, if they exist at all. We observed no consistent racial differences in immune gene expression or TIL counts in TNBC by race. However, this study cannot rule out small differences in immune cell subtype distribution and activity status that may not be apparent in bulk RNA analysis.

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Loss of PTEN in high grade advanced stage triple negative breast ductal cancers in African American women.

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Loss of PTEN in high grade advanced stage triple negative breast ductal cancers in African American women.

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