Mamta Gurav

Evidence for the association of Epstein‐Barr Virus in breast cancer in Indian patients using in‐situ hybridization technique

Epstein‐Barr Virus (EBV) is etiologically linked to Burkitt lymphoma (BL), nasopharyngeal carcinoma, post‐transplant lymphomas, Hodgkin disease, and possibly other tumors. However, the association of oncogenic EBV with breast carcinoma (BC) is still controversial and a matter of debate. We aimed to study the presence of EBV genome in BC cases in Indian patients and its association with the clinicopathological features. The formalin fixed paraffin embedded tissues from 83 women with primary invasive BC were studied for the presence of EBV by in‐situ hybridization (ISH) technique for Epstein‐Barr Virus Encoded RNA (EBER) with appropriate controls. Correlation of EBER‐ISH positivity with clinicopathological features was performed using Fisher exact test and P<.05 was considered as significant. Eighty‐three BC cases were comprised of 47 (56.5%) triple negative breast cancers (TNBC), 17 (20.5%) hormone positive and 19 (22.9%) HER2 positive cases. Of 83 cases, 25 cases (30.1%) were positive for EBER‐ISH test. The positivity was restricted to the tumor cells and not seen in the surrounding breast lobules. EBER‐ISH positivity was statistically associated with larger tumor size (52.6% in >5 cm tumors vs 19.3% in ≤5 cm; P=.014) and with TNBCs (21/47 [44.7%] in TNBCs vs 4/36 [11.1%] in non‐TNBCs; P=.001). A possible causal association of EBV in BC cases in Indian patients is suggested by high frequency of EBER‐ISH positivity noted in our study. This might have therapeutic significance because of the possible role of EBV specific cytotoxic T cells in targeting EBV associated tumor cells and can be considered as a potential targeted therapy. To the best of our knowledge, this is the first study from India to address this issue using EBER‐ISH technique.

Unraveling the spectrum of KIT mutations in gastrointestinal stromal tumors: An Indian Tertiary Cancer Center Experience

Background: Primary mutations in the KIT gene are the driving force for gastrointestinal stromal tumors (GIST) tumorigenesis. Predictive role of KIT mutation status aids oncologists in patient management. There is a paucity of comprehensive data on the frequency of mutations in the KIT gene in GIST affecting Indian patients. The aims of this study were to determine the frequency and spectrum of molecular alterations affecting the KIT gene and assess their association with clinicopathologic features in a cohort of patients of GIST. Materials and Methods: Morphological and immunohistochemically confirmed GIST cases (n = 114) accessioned from August 2014-June 2015 were analyzed for mutations in KIT exons 9, 11, 13, and 17 and subjected to Sanger sequencing onto the ABI 3500 Genetic Analyzer. The sequences were analyzed using sequence analysis software: SeqScape® and Chromas Lite. Results: KIT mutations were seen in 70% of cases and the majority of KIT mutations involved exon 11 (57%), followed by exon 9 (10%), exon 13 (3%), and exon 17 (1%). Most common exon 11 mutations were in-frame deletions (61.4%) followed by substitution mutations (19.3%). Exon 9 mutations showed identical duplication of Ala-Tyr at codons 502–503. Simultaneous mutations affecting exon 11 and 13 were discovered. Novel variations, namely, p.Q556E (c.1666C>G), p.Q556dup (c.1666_1668dupCAG), p.K558_V559delinsS (c.1672_1677delAAGGTTinsAGT), p.Y503_F504insTY (c.1509_1510insACCTAT), and p.K642R (c.1925A>G) involving exons 11, 9, and 13, respectively, were observed. Interpretation and Conclusions: First study with complete analysis of all 4 exons of KIT (exons 9, 11, 13, and 17) in Indian GIST patients. Along with well-described KIT mutations, several rare double mutations as well as novel alterations were reported in this series.

Diffuse glioma – Rare homozygous IDH point mutation, is it an oncogenetic mechanism?

Isocitrate dehydrogenase (IDH1/IDH2) mutations in gliomas of WHO grade II/III and secondary glioblastoma are almost always heterozygous missense mutations. Here, we report an extremely rare case of homozygous IDH1R132H mutation in a recurrent WHO grade III anaplastic astrocytoma. The authors here also review the relevant literature for the possible metabolic impact of homozygous IDH1/2 mutations in the gliomagenesis.

MPTH-07GLIOBLASTOMAS: CORRELATION OF MGMT GENE PROMOTER METHYLATION WITH CLINICO-PATHOLOGICAL AND MOLECULAR PARAMETERS

Methylation of O6-methylguanine DNA methyltransferase (MGMT) is one of the predictive and prognostic markers of glioblastomas (GBMs). In this study, GBMs have been evaluated for the same and correlated with other clinicopathological and molecular parameters. MATERIALS AND METHODS: Diagnosed cases of GBM, during the period of June 2014 to December 2014 in the Department of Pathology of our Institute, wherein they have been evaluated for MGMT methylation by methylation specific polymerase chain reaction, IDH1R132H and p53 protein expression by immunohistochemistry and EGFR gene amplification by fluorescence in-situ hybridisation formed the study sample. Statistical correlation was done by Chi-square and Fischers exact, using IBM SPSS Software 16 version. RESULTS: A total of 97 cases of GBM formed the study sample with age range of 20-75 years (mean age:49.76 years) and male: female ratio of 3.2:1 (M:74;F:23).Cerebral hemispheric location was commonest (frontal:35%; temporal:43 & parietal:19%). 46 (47.4%) cases were MGMT methylated (low methylation: 10) and 51 were unmethylated. 23 out of 84 cases (27.4%) were EGFR amplified; 10 cases (10.3%) were positive for IDH1R132H; 16 showed loss of ATRX protein expression (of which 7 were IDH1R132H positive; while the other 3 IDHR132H positive cases showed retained ATRX protein). Of the 46 MGMT methylated cases, 10 were EGFR amplified (10 out of 23 EGFR amplified cases were MGMT methylated); 5 were IDH1R132H positive and 6 showed loss of ATRX expression. None of the molecular markers showed any correlation for the histological features of calcification and necrosis (neither for pseudopalisading or confluent). CONCLUSIONS: MGMT was methylated in 47.4%of GBMs and had no significant statistical correlation with EGFR gene amplification, IDH1R132H mutation, ATRX protein expression and other histomorphological features. This study did not identify any surrogate marker for MGMT promoter methylation.