Epigenetic deregulations of Wnt/β-catenin and transforming growth factor beta-Smad pathways in esophageal cancer: Outcome of DNA methylation

Background: Promoter methylation of tumor suppressor genes (TSGs) is a well-reported portent in carcinogenesis; hence, it is worthy to investigate this in high-risk Northeast population of India. The study was designed to investigate methylation status of 94 TSGs in esophageal squamous cell carcinoma (ESCC). Further, the effect of OPCML promoter methylation on gene expression was analyzed by immunohistochemistry. Moreover, in silico protein–protein interactions were examined among 8 TSGs identified in the present study and 23 epigenetically regulated genes reported previously by our group in ESCC. Materials and Methods: Methylation profiling was carried out by polymerase chain reaction array and OPCML protein expression was examined by tissue microarray-based immunohistochemistry. Results: OPCML, NEUROG1, TERT, and WT1 genes were found hypermethylated and SCGB3A1, CDH1, THBS1, and VEGFA were hypomethylated in Grade 2 tumor. No significant change in OPCML expression was observed among control, Grade 1, and Grade 2 tumor. Conclusively, hypermethylation of the studied OPCML promoter in Grade 2 tumor produced no effect on expression. Unexpectedly, OPCML expression was downregulated in Grade 3 tumor in comparison to other groups signifying that downregulation of OPCML expression may lead to higher grade of tumor formation at the time of diagnosis of ESCC in patients. Significant interactions at protein level were found as VEGFA:PTK2, CTNNB1:CDH1, CTNNB1:VEGFA, CTNNB1:NEUROG1, CTNND2:CDH1, and CTNNB1:TERT. These interactions are pertinent to Wnt/β-catenin and TGF-β-Smad pathways. Conclusions: Deranged OPCML expression may lead to high-grade ESCC as well as epigenetically regulated genes, that is, CDH1, CTNNB1, CTNND2, THBS1, PTK2, WT1, OPCML, TGFB1, and SMAD4 may alter the Wnt/β-catenin and TGF-β-Smad pathways in ESCC. Further study of these genes could be useful to understand the molecular pathology of ESCC with respect to epithelial-mesenchymal transition (EMT) mediated by Wnt/β-catenin and TGF-β signaling pathways

Copy number polymorphism of glutathione-S-transferase genes (GSTM1 & GSTT1) in susceptibility to lung cancer in a high-risk population from north-east India.

Background & objectives: Genetic polymorphisms in glutathione-S-transferase genes (GSTM1 and GSTT1) have been studied intensively for their potential role in lung cancer susceptibility. However, most of the studies on association between the polymorphisms and lung cancer do not distinguish between genotypes with one or two copies of the genes. The present study investigates the gene dosage effects of GSTT1 and GSTM1 copy number and their environmental interactions to examine the association of lung cancer risk with trimodular genotypes of the GSTs in a high-risk population from north-east India. Methods: A total of 154 lung cancer cases and 154 age and sex matched controls from the high risk region of north-east India were analyzed by multiplex real-time PCR to determine the trimodal genotypes (+/+, +/- and -/-) in both the genes (GSTM1 and GSTT1). Results: No significant association and gene dosage effect of GSTM1 gene copy number with lung cancer risk (Ptrend=0.13) were found. However, absence of GSTT1 conferred 68 per cent (OR=0.32;95%CI=0.15-0.71;P=0.005) reduced risk compared to the two copy number of the gene. tThere was evidence of gene dosage effect of GSTT1 gene (Ptrend=0.006). Tobacco smoking was a major environmental risk factor to lung cancer (OR=3.03;95%CI=1.73-5.31;P<0.001). However, its interaction with null genotype of GSTT1 conferred significant reduced risk to lung cancer (OR=0.30;95%CI=0.10-0.91;P=0.03). Further in only tobacco smokers, null genotype was associated with increased reduced risk [0.03(0.001-0.78)0.03; Ptrend=0.006]. No effect modification of GSTM1 was observed with lung cancer risk by environmental risk factors. Interpretation & conclusions: The results suggest that absence of GSTT1 null genotype may be associated with a reduced risk of lung cancer and the effect remains unchanged after interaction with smoking.

Subcutaneous panniculitis-like T-cell cutaneous lymphoma.

Subcutaneous panniculitis-like T cell lymphoma (SPTCL) is a rare cytotoxic T-cell lymphoma classified in the World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification as a unique extranodal lymphoma with characteristic by T cell receptor (TCR) gene rearrangement. We report here a case of SPTCL in a 22 year-old woman who had presented with variably sized multiple nodules on both her legs. Initial differential diagnoses considered were panniculitis and lupus panniculitis. The histopathology showed a predominantly subcutaneous lobular infiltrate with atypical lymphocytes, karyorrhexis and rimming of adipocytes by lymphoid cells. Immunohistochemistry showed CD4-, CD8+, CD56- T-cell phenotype. Although TCR rearrangement studies were not done, the above T-cell phenotype and sparing of epidermis and dermis suggested the possibility of an SPTCL alpha/beta type. The patient received five cycles of a cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) regimen which resulted in the regression in her skin lesions and constitutional symptoms.

An unusual presentation of primary lymphoma of the thyroid in a young male patient.

Primary lymphoma of the thyroid gland is a rare disease that is strongly associated with chronic lymphocytic thyroiditis. We report an unusual case of 20-year-old male who presented with thyroid swelling and was diagnosed on cytology as lymphocytic thyroidtis. However, histopathologicalfindings revealed non-Hodgkin's lymphoma that was further classified as B-cell type on immunohistochemical stains. In cytology, lymphomas must be considered as a differential diagnosis in case of Hashimoto's/lymphocytic thyroiditis, subacute thyroiditis and small cell carcinoma.

The role of p53 and anaplastic lymphoma kinase genes in the progression of cutaneous CD30(+) lymphoproliferative diseases.

BACKGROUND AND OBJECTIVES: Molecular events that precede transformations from lymphomatoid palulosis (LyP) to mycosis fungoides (MF) or to cutaneous anaplastic large cell lymphoma (ALCL) in the CD 30(+) cutaneous lymphoproliferative diseases (LPDs) are not known. Altered p(53) gene may be responsible since overexpression of the p(53) gene product has been reported in higher, but not in lower grades of cutaneous lymphomas. Expression of the anaplastic lymphoma kinase (ALK) gene product has also been described as an important prognostic indicator in ALCL. ALK positive systemic nodal ALCL are associated with a good prognosis. However, primary cutaneous ALCL that are ALK negative have a better overall survival. The current study was done to see if mutated p(53) gene or ALK reactivity were poor prognostic indicators in those patients with CD 30(+) cutaneous LPD who showed progression of the disease. METHODS: Mutations of the p(53) gene and expression of the ALK gene product were analysed in 36 patients (23 of LyP and 13 of CD30(+) cutaneous ALCL). Follow up data were available up till 5 yr in all patients. RESULTS: Clinical progression or histological transformation in sequential biopsy specimens was found in 9 of 36 patients. Transformation occurred in 5 patients (4 from LyP to ALCL and 1 from MF to ALCL) and clinical progression in 4 patients with ALCL. Mutations of the p(53) gene were found in two biopsy specimens of LyP. ALK gene products were not detected in any of the biopsy specimens of LyP and primary cutaneous ALCL. INTERPRETATION AND CONCLUSION: Although 9 of 36 patients with cutaneous CD30(+) LPDs had progression of their disease, neither mutations of the p(53) gene nor ALK immunoreactivity were found in any of these biopsies. The two cases of LyP that had mutated p(53) gene in their biopsy specimens showed no progression of their disease in the 5 yr follow up period. It appears that these molecular events may not play any significant role in the pathogenesis, progression or transformation of cutaneous CD30(+) LPD.