Mitochondrial DNA copy number and risk of oral cancer: a report from Northeast India.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the sixth most common cancer globally. Tobacco consumption and HPV infection, both are the major risk factor for the development of oral cancer and causes mitochondrial dysfunction. Genetic polymorphisms in xenobiotic-metabolizing enzymes modify the effect of environmental exposures, thereby playing a significant role in gene-environment interactions and hence contributing to the individual susceptibility to cancer. Here, we have investigated the association of tobacco - betel quid chewing, HPV infection, GSTM1-GSTT1 null genotypes, and tumour stages with mitochondrial DNA (mtDNA) content variation in oral cancer patients. METHODOLOGY/PRINCIPAL FINDINGS: The study comprised of 124 cases of OSCC and 140 control subjects to PCR based detection was done for high-risk HPV using a consensus primer and multiplex PCR was done for detection of GSTM1-GSTT1 polymorphism. A comparative ΔCt method was used for determination of mtDNA content. The risk of OSCC increased with the ceased mtDNA copy number (Ptrend  = 0.003). The association between mtDNA copy number and OSCC risk was evident among tobacco - betel quid chewers rather than tobacco - betel quid non chewers; the interaction between mtDNA copy number and tobacco - betel quid was significant (P = 0.0005). Significant difference was observed between GSTM1 - GSTT1 null genotypes (P = 0.04, P = 0.001 respectively) and HPV infection (P<0.001) with mtDNA content variation in cases and controls. Positive correlation was found with decrease in mtDNA content with the increase in tumour stages (P<0.001). We are reporting for the first time the association of HPV infection and GSTM1-GSTT1 null genotypes with mtDNA content in OSCC. CONCLUSION: Our results indicate that the mtDNA content in tumour tissues changes with tumour stage and tobacco-betel quid chewing habits while low levels of mtDNA content suggests invasive thereby serving as a biomarker in detection of OSCC.

Post irradiation spindle cell carcinoma of tonsillar pillar.

Spindle cell carcinoma of the tonsillar pillar is a rare malignancy. A case of spindle cell carcinoma of the anterior tonsillar pillar in a 59-year-old man is presented. A growth on the anterior tonsillar pillar, measuring 9 × 7 × 6 mm, was resected. The neoplasm occurred as a complication of radiotherapy (excessive cumulative radiation dose of 60 Gray) for carcinoma larynx with a latency period of three years. Postradiation spindle cell carcinoma is an uncommon disease manifesting as sarcoma in a previously irradiated field, usually with a latent period of 5 years or more. Literature is limited to small series. Histologically, this tonsillar growth was composed of a squamous cell carcinoma (epithelial component) and a spindle cell sarcomatous component. The two components of the tumour were confirmed using the immunohistochemical staining (cytokeratin and vimentin). Further p53 positivity of the sarcomatous elements aided in ruling out radiation-induced nonmalignant changes of mesenchymal tissue. This paper discusses this rare tumour in a common setting.

Intraoperative scrape cytology: Adult granulosa cell tumor of ovary.

Adult granulosa cell tumor is often a hormonally active stromal cell neoplasm of the ovary with malignant potential. Intra-operative pathological assessment is a valuable tool in guiding optimal surgical treatment in patients. Of the various intra-operative cytological diagnostic modalities, scrape smear cytology is an effective, economical, simple, fast and reliable method with results comparable with frozen section diagnosis. We describe a case of adult granulosa cell tumor in a 30-years-old lady diagnosed on intra-operative scrape cytology, and further reconfirmed on frozen section and histopathology.