Anterior tongue cancer with no history of tobacco and alcohol use may be a distinct molecular and clinical entity.

BACKGROUND: A small, albeit significant, number of head and neck squamous cell carcinoma (HNSCC) patients has no history of tobacco and alcohol use. Such non-habits associated HNSCCs may represent a distinct clinical entity and exhibit increased aggressiveness. The objective of the study was to understand differences in molecular etiology of habits, and non-habits associated tongue carcinomas. MATERIALS AND METHODS: High-throughput gene expression profiling of 22 tumor samples was carried out. This was followed by quantitative real-time PCR validation of four of the identified differentially expressed genes. RESULTS AND CONCLUSION: Eighteen genes were identified that correlate strongly with the habits- and non-habits distinction. Among the genes significantly overexpressed in the non-habits group are CCND1, a key cell-cycle regulator, DACT3, a modulator of the Wnt/beta-catenin pathway, and three genes associated with the Notch signaling pathway. CCND1 and DACT3 overexpression in non-habits associated tongue carcinomas were subsequently validated by quantitative real-time PCR in an independent cohort (n = 18) of patient samples. Gene expression data were integrated with publicly available protein interaction data to build a small protein interaction network containing five of 18 differentially expressed genes. This suggested that a functional 'network module' can be implicated in the subgroup distinction. All the tumors analyzed here were human papillomavirus (HPV) negative samples. An association between CCND1 overexpression in oral tumors and poor prognosis has previously been reported. Thus, CCND1 overexpression in non-habits associated anterior tongue carcinomas may contribute to their increased clinical aggressiveness.

A miR-centric view of head and neck cancers.

Head and Neck Squamous Cell Carcinomas (HNSCCs) constitute the sixth most common cancer worldwide with an average 5-year survival rate of around 50%. Several microRNAs, small non-coding RNAs involved in post-transcriptional gene regulation, have been linked to HNSCC based on their differential expression in tumors. Here, we present a compilation of multiple types of information on each HNSCC linked miRNA including their expression status in tumors, their molecular targets relevant to cancer, results of gene manipulation studies and association with clinical outcome. Further, we use this information to devise a new scheme for classifying them into causal and non-causal miRNAs in HNSCC. We also discuss the possibility of using miRNAs as prognostic and diagnostic biomarkers for HNSCC, based on existing literature. Finally, we present available evidence that shows how altered expression of specific miRNAs can contribute to various "hallmarks of cancer" phenotypes such as limitless replicative potential owing to abnormal cell cycle regulation, evasion of apoptosis, reduced response to anti-growth signals, and Epithelial-Mesechymal transition (EMT).

Molecular variants of HPV-16 associated with cervical cancer in Indian population.

Human papilloma virus is a causative factor in the etiology of cervical cancer with HPV16 being the most prevalent genotype associated with it. Intratype variations in oncogenic E6/E7 and capsid L1 proteins of HPV 16 besides being of phylogenetic importance, are associated with risk of viral persistence and progression. The objective of this multicentric study was to identify HPV-16 E6, E7 and L1 variants prevalent in India and their possible biological effects. Squamous cell cervical cancer biopsies were collected from 6 centres in India and examined for the presence of HPV 16. Variants of HPV-16 were characterized by full length sequence analysis of L1, E6 and E7 genes in 412 samples. Similar distribution of the variants was seen from the different centres/regions, with the European variant E350G being the most prevalent (58%), followed by American Asian variant (11.4%). Fifty six changes were seen in E6 region, 31 being nonsynonymous. The most frequent being L83V (72.3%), Q14H (13.1%) and H78Y (12.1%). Twenty-nine alterations were seen in E7 region, with 12 being nonsynonymous. The most frequent being F57V (9%). L1 region showed 204 changes, of which 67 were nonsynonymous. The most frequent being 448insS (100%), and 465delD (100%), H228D (94%), T292A (85%). The identified variants some new and some already reported can disrupt pentamer formation, transcriptional regulation of the virus, L1 protein interface interaction, B and T cell epitopes, p53 degradation, and thus their distribution is important for development of HPV diagnostics, vaccine, and for therapeutic purpose.

Mutational analysis of Smad7 in human cervical cancer.

Our aim was to carry out mutational analysis of Smad7 exon 4 that codes for the Smad7 MH2 domain in human cervical cancer tissues. This study is warranted since genetic abnormalities of components of the transforming growth factor-beta (TGF-beta)/Smad signaling system have been implicated in a variety of human cancers. Further, Smad7 is an important member of the Smad family that functions as a negative feedback regulator of TGF-beta responses. By direct sequencing, we screened 60 histopathologically confirmed human cervical carcinomas for mutations in exon 4 of Smad7 that encodes the MH2 domain of the protein, a region of the protein believed to be critical for receptor interaction. No mutations or aberrations could be identified in any of the 60 analyzed tumor samples. However, we identified a previously reported, heterozygous, silent G to C variant in codon 391 of Smad7 that was found twice in the set of 60 clinical samples. Thirty of the clinical samples analyzed in the study were positive for the presence of high-risk human papillomavirus (HPV) subtypes, while the rest were oncogenic HPV-negative. The two instances of the silent variant was found in oncogenic HPV-negative samples. We report mutational analysis of Smad7 in cervical cancer for the first time. Mutations and variants of Smad7 are unlikely to be of major significance to the pathogenesis of HPV-induced cervical cancer.