SUSANTA ROY CHOUDHURY
Articles written in Journal of Genetics
Volume 70 Issue 3 December 1991 pp 169-179
Fish ribosomal RNA genes (rDNA) have been compared by restriction endonuclease digestion followed by Southern hybridization using rRNA or cloned rRNA genes as labelled probes. In several species belonging to the orders Cypriniformes and Perciformes, the simple restriction patterns revealed a high degree of size class homogeneity among the rDNA repeats and similar restriction map within a species. Different species have different restriction patterns and fragment lengths arising mostly out of different length of the nontranscribed spacer. Polymorphic restriction sites are present in some species. The species-specific differences in fragment lengths produced in rDNA by some restriction enzymes can thus be used to study interspecific fish hybrids.
Volume 95 Issue 3 September 2016 pp 551-563 RESEARCH ARTICLE
The aim of the study was to understand the role of SLIT2–ROBO1/2–CDC42 signalling pathways in development of breast cancer (BC). Primary BC samples (n = 150), comprising of almost equal proportion of four subtypes were tested for molecular alterations of SLIT2, ROBO1, ROBO2 and CDC42, the key regulator genes of this pathway. Deletion and methylation frequencies of the candidate genes were seen in the following order: deletion, SLIT2 (38.6%) > ROBO1 (30%)> ROBO2 (7.3%); methylation, SLIT2 (63.3%) > ROBO1 (26.6%) >ROBO2 (9.3%). Majority (80%, 120/150) of the tumours showed alterations (deletion/methylation) in at least one of the candidate genes. Overall, alterations of the candidate genes were as follows: SLIT2, 75.3% (101/150); ROBO1, 45.3% (68/150); ROBO2, 15.3% (23/150). Significantly, higher alteration of SLIT2 locus was observed in triple negative breast cancer (TNBC) over HER2 subtype (P = 0.0014). Similar trend is also seen in overall alterations of SLIT2 and/or ROBO1, in TNBC than HER2 subtype (P = 0.0012); of SLIT2 and/or ROBO2 in TNBC than luminal A (P = 0.014) and HER2 subtype (P = 0.048). Immunohistochemical analysis of SLIT2, ROBO1/2 showed reduced expression, concordant with their molecular alterations. Also, high expression of total CDC42 (49/52; 94.2%) and reduced expression of phospho Serine-71 CDC42 (41/52; 78.8%) was observed. Coalterations of SLIT2 and/or ROBO1, SLIT2 and/or ROBO2 had significant association with reduced expression of phospho Serine-71 CDC42 (P = 0.0012–0.0038). Alterations of SLIT2 and/or ROBO1, reduced expression of phospho Serine-71 CDC42 predicted poor survival of BC patients. Results indicate the importance of SLIT2–ROBO1–CDC42 signalling pathway in predicting tumour progression.
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