Jabed Iqbal

Loss of androgen receptor expression predicts early recurrence in triple-negative and basal-like breast cancer.

Treatment of triple-negative invasive breast cancers, defined by the absence of estrogen and progesterone receptors and c-erbB2 expression, remains challenging. Androgen receptor, a member of the nuclear receptor superfamily that is involved in signaling pathways regulating cell proliferation, has been implicated in breast tumorigenesis. We immunohistochemically examined the expression of androgen receptor, basal markers (CK14, 34βE12) and EGFR in 699 triple-negative invasive breast cancers in tissue microarrays using the streptavidin–biotin method, and correlated the findings with clinical outcome. Positive androgen receptor expression was defined as staining of 1% or more of tumor cell nuclei. Survival outcomes were estimated with the Kaplan–Meier method and compared between groups with log-rank statistics. Cox proportional hazards models were used to determine the effect of androgen receptor on survival outcomes. Immunohistochemical positivity was observed in 38% of tumors, with the proportion of stained tumor cells ranging from 1 to 95% (mean 29%, median 10%). Androgen receptor expression was inversely associated with histologic grade and mitotic score. CK14, 34βE12 and EGFR confirmed 85% of cases to be basal-like, without significant association of basal-like phenotype with androgen receptor expression. Disease-free survival was significantly better in androgen receptor-positive triple-negative breast cancer, with a trend for improved overall survival. Decreased recurrence likelihood in both triple-negative and basal-like tumors (hazard ratio, 0.704; 95% confidence intervals, 0.498–0.994; P=0.0464; and hazard ratio, 0.675; 95% confidence intervals, 0.468–0.974; P=0.0355, respectively) was noted within 5 years of diagnosis but not thereafter. Our study suggests that loss of androgen receptor in triple-negative breast cancers augurs a worse prognosis, including those with basal-like features. More work in elucidating its relationship with mechanisms of progression, as well as trials of targeted treatment for androgen receptor-expressing triple-negative tumors, needs to be performed.

PD1 blockade with pembrolizumab is highly effective in relapsed or refractory NK/T-cell lymphoma failing L-asparaginase

Natural killer (NK)/T-cell lymphomas failing L-asparaginse regimens have no known salvage and are almost invariably fatal. Seven male patients with NK/T-cell lymphoma (median age, 49 years; range, 31-68 years) for whom a median of 2 (range, 1-5) regimens (including l-asparaginase regimens and allogeneic hematopoietic stem-cell transplantation [HSCT] in 2 cases) failed were treated with the anti-programmed death 1 (PD1) antibody pembrolizumab. All patients responded, according to various clinical, radiologic (positron emission tomography), morphologic, and molecular (circulating Epstein-Barr virus [EBV] DNA) criteria. Two patients achieved complete response (CR) in all parameters. Three patients achieved clinical and radiologic CRs, with two having molecular remission (undetectable EBV DNA) but minimal EBV-encoded RNA-positive cells in lesions comprising predominantly CD3+CD4+ and CD3+CD8+ T cells (which ultimately disappeared, suggesting they represented pseudoprogression) and one having detectable EBV DNA despite morphologic CR. Two patients achieved partial response (PR). After a median of 7 (range, 2-13) cycles of pembrolizumab and a follow-up of a median of 6 (range, 2-10) months, all five CR patients were still in remission. The only adverse event was grade 2 skin graft-versus-host disease in one patient with previous allogeneic HSCT. Expression of the PD1 ligand was strong in 4 patients (3 achieving CR) and weak in 1 (achieving PR). PD1 blockade with pembrolizumab was a potent strategy for NK/T-cell lymphomas failing l-asparaginase regimens.

Triple Negative Breast Cancer: Outcome Correlation With Immunohistochemical Detection of Basal Markers

We earlier evaluated the relationship of 653 triple negative breast cancers (TNBC) with basal immunophenotypic expression by using antibodies to basal cytokeratins (CK5/6, CK14, CK17, 34βE12), p63, smooth muscle actin (SMA), epidermal growth factor receptor, and CD117, and found that a triple panel of CK14, 34βE12 and epidermal growth factor receptor determined 84% of our cases to be basal-like. Women with basal-like TNBC tended to be younger (P=0.04), have histologically higher-grade tumors (P=0.047), with positive nodal status (P=0.047), than those whose tumors were nonbasal-like. Using univariate Cox regression analysis, tumor size (P=0.003), histologic grade (P=0.006), and nodal status (P=0.017) were significant factors for disease-free survival (DFS) among TNBC, whereas age (P=0.004), tumor size (P=0.001), histologic grade (P<0.001), nodal status (P=0.011), lymphovascular invasion (P=0.032), and pushing borders (P=0.042) were important for overall survival (OS). On multivariate analysis, age was statistically significant for both DFS and OS (P=0.033, 0.001 respectively), whereas histologic grade was important for OS (P<0.001). Kaplan Meier curves showed CK17 positivity to impact adversely on DFS (P=0.003) and OS (P=0.014), whereas CD117 positive staining was accompanied by diminished OS (P=0.036). SMA expression in TNBC however, revealed a trend for improved DFS (P=0.05). Our findings indicate that basal-like TNBC are associated with adverse clinicopathologic parameters, and that individual biologic markers of CK17, CD117, and SMA have prognostic implications on survival. Possibilities exist for future targeted therapy for this challenging group of breast cancers.

EGFR Mutation Testing Practices within the Asia Pacific Region: Results of a Multicenter Diagnostic Survey

Introduction: The efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in EGFR mutation-positive non–small-cell lung cancer (NSCLC) patients necessitates accurate, timely testing. Although EGFR mutation testing has been adopted by many laboratories in Asia, data are lacking on the proportion of NSCLC patients tested in each country, and the most commonly used testing methods. Methods: A retrospective survey of records from NSCLC patients tested for EGFR mutations during 2011 was conducted in 11 Asian Pacific countries at 40 sites that routinely performed EGFR mutation testing during that period. Patient records were used to complete an online questionnaire at each site. Results: Of the 22,193 NSCLC patient records surveyed, 31.8% (95% confidence interval: 31.2%–32.5%) were tested for EGFR mutations. The rate of EGFR mutation positivity was 39.6% among the 10,687 cases tested. The majority of samples were biopsy and/or cytology samples (71.4%). DNA sequencing was the most commonly used testing method accounting for 40% and 32.5% of tissue and cytology samples, respectively. A pathology report was available only to 60.0% of the sites, and 47.5% were not members of a Quality Assurance Scheme. Conclusions: In 2011, EGFR mutation testing practices varied widely across Asia. These data provide a reference platform from which to improve the molecular diagnosis of NSCLC, and EGFR mutation testing in particular, in Asia.

Role of inflammatory infiltrates in triple negative breast cancer

Triple negative breast cancer (TNBC) is a heterogenous disease often characterised by aggressive biology and poor prognosis. Efforts to precisely treat TNBC have been compounded by the lack of specific therapeutic molecular targets. Recent transcriptomic studies have revealed, among others, an immunomodulatory subtype of TNBC, whereby activated immune response genes are associated with good prognosis. Since then, a great deal of effort has been made to understand the immune microenvironment of some TNBC subtype, which comprises several immune cell populations including lymphocytes and macrophages. There is increasing evidence that the basal subtype may be significantly regulated by tumour-infiltrating T-cells and that high levels of tumour-infiltrating CD8+ T-cells may be a reflection of improved prognosis with chemotherapy sensitivity in TNBC. On the other hand, tumour-associated macrophages have been associated with a relatively poor outcome in TNBC. Comparison of the immune signatures in TNBC with non-TNBC may furthermore help us to understand these immune mechanisms potentially leading to new therapeutic approaches. Within this short review, we discuss the current scientific evidence regarding (a) the role of tumour-infiltrating lymphocytes in the clinical outcome in TNBC and (b) the newly discovered immunomodulatory genotype that may provide for a therapeutic target in TNBC.

MED12 is frequently mutated in breast phyllodes tumours: a study of 112 cases

Aim To determine the frequency of MED12 mutations in a series of 112 breast phyllodes tumours, and to correlate the findings with clinicopathological parameters and survival outcomes. Methods Phyllodes tumours from the Department of Pathology, Singapore General Hospital, were classified into benign, borderline and malignant categories. Genomic DNA from formalin-fixed paraffin-embedded phyllodes tumours was extracted, purified and subjected to ultra-deep-targeted amplicon sequencing across exon 2 of the MED12 gene. Sequencing was performed on the Illumina MiSeq next-generation sequencing platform and bioinformatics analysis applied. Appropriate statistical analyses were carried out. Results There were 66 benign, 32 borderline and 14 malignant tumours, with 43 (65.1%), 21 (65.6%) and 6 (42.8%) disclosing MED12 mutations (missense, splice site, indel), respectively. For 97 cases with available follow-up, there were 10 (10.3%) recurrences. Patients with phyllodes tumours that harboured MED12 mutations experienced improved disease-free survivals, with higher recurrence likelihood in those without MED12 mutations (HR 9.99, 95% CIs 1.55 to 64.42, p=0.015). Conclusions Similar to fibroadenomas, phyllodes tumours show a high frequency of MED12 mutations, affirming the close biological relationship between these fibroepithelial neoplasms.

Breast cancer stem cells: an update.

Breast cancer is a significant cause of morbidity and mortality in women with a high incidence of recurrence or treatment failure. Growing evidence suggests that cancer stem cells (CSCs) most likely contribute to tumour progression, spread and therapy failure. However, despite extensive research and the tremendous clinical potential of such cells in possible therapeutic management, the real nature of CSCs remains an enigma. In this review, we discuss the fundamental properties and molecular target of CSCs and focus on recent advances regarding the identification of CSC markers with emphasis on breast cancer and the underlying molecular mechanism of CSC phenotypes. We also discuss experimental evidence of targeting molecular pathways in order to modulate breast CSC behaviour in tumourigenesis and the controversies associated with it that potentially weaken the CSC model in breast cancer and other cancers as well.

Insulin growth factor receptor-1 expression and loss of PTEN protein predict early recurrence in triple-negative breast cancer.

Iqbal J, Thike A A, Cheok P Y, Tse G M‐K & Tan P H 
(2012) Histopathology 61, 652–659

Ductal carcinoma in situ associated with triple negative invasive breast cancer: evidence for a precursor-product relationship.

Aim We evaluated pathological features of the ductal carcinoma in situ component of 241 triple negative invasive breast cancers. Results We found that 151 (62.6%) in situ lesions were of high nuclear grade, and 236 (97.9%) were triple negative (oestrogen receptor, progesterone receptor, cerbB2 negative). Immunohistochemistry for cytokeratin (CK)5/6, CK14, CK17, epidermal growth factor receptor (EGFR), CD117, 34βE12, p63 and smooth muscle actin (SMA) revealed positive staining in 5 (2.1%), 60 (24.9%), 69 (28.6%), 37 (15.4%), 69 (28.6%), 137 (56.8%), 3 (1.2%) and 22 (9.1%) in situ ductal components respectively, with fair to substantial agreement of staining results (positive versus negative) between in situ and corresponding invasive elements for CK5/6, CK14, CK17, EGFR, CD117 and 34βE12; but none to fair agreement for p63 and SMA respectively. When the tri-panel of CK14, EGFR and 34βE12 was used to define the basal phenotype, 68% revealed basal-like expression of both in situ and invasive components of the same case. Conclusions Our data support the notion that triple negative ductal carcinoma in situ is the precursor of the corresponding invasive counterpart, and that basal-like expression is maintained in the majority of invasive cancers associated with basal-like in situ disease. Future studies that prospectively evaluate morphological and biological characteristics of invasive cancers that develop from triple negative and basal-like ductal carcinoma in situ lesions will assist in validating these findings.

HER2/neu revisited: quality and interpretive issues

Background Immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH) are the only tests currently approved by the US Food and Drug Administration for classifying which patients will benefit from trastuzumab therapy. The accuracy of these two testing methods can be adversely affected by a variety of pre-analytical, analytical and post-analytical factors. According to the latest published recommendations of the panel of the Joint Committee of the American Society of Clinical Oncology and College of American Pathologists for HER2/neu testing, laboratories performing IHC and FISH for HER2/neu status in breast cancer are now required to have a high concordance of at least 95% between IHC and FISH, significantly higher than that in the published literature. Aim To perform a retrospective analysis of the concordance of IHC and FISH analysis for HER2/neu at Singapore General Hospital and review potential causes of disparity between these two methods. Method A retrospective review of a total of 106 invasive ductal carcinomas evaluated for HER2/neu at the Department of Pathology, Singapore General Hospital between 2007 and 2008 were included in the study. The initial HER2/neu immunostained slides were reviewed independently without knowledge of FISH results, and concordance between IHC and FISH was determined. Results Concordance between IHC and FISH assay was excellent and within the published range (104/106=98.1%). The discordant cases represent a well-recognised subset of genetic heterogeneity in HER2/neu, which is known to contribute to positive IHC and negative FISH tests.