Survivin: A molecular biomarker in cancer.

Survivin, a member of the inhibitor of apoptosis (IAP) protein family that inhibits caspases and blocks cell death, is highly expressed in most cancers and is associated with a poor clinical outcome. Survivin has consistently been identified by molecular profiling analysis to be associated with high tumour grade cancers, different disease survival and recurrence. Polymorphisms in the survivin gene are emerging as powerful tools to study the biology of the disease and have the potential to be used in disease prognosis and diagnosis. The survivin gene polymorphisms have also been reported to influence tumour aggressiveness as well as survival of cancer patients. The differential expression of survivin in cancer cells compared to normal tissues and its role as a nodal protein in a number of cellular pathways make it a high target for different therapeutics. This review discusses the complex circuitry of survivin in human cancers and gene variants of survivin, and highlights novel therapy that targets this important protein.

Raising cut-off value of prostate specific antigen (PSA) for biopsy in symptomatic men in India to reduce unnecessary biopsy.

Background & objectives: The characteristics of prostate specific antigen (PSA) for trans-rectal ultrasonography guided prostate biopsy in men with lower urinary tract symptoms (LUTS) are not well defined. This study was carried out to analyse the threshold of PSA for biopsy in symptomatic men in India. Methods: From January 2000 to June 2011, consecutive patients who had digital rectal examination (DRE) and PSA testing done for LUTS were included in this study. PSA was done with ELISA technique. Patients with acute or chronic prostatitis, prostatic abscess, history of surgery on prostate within the previous three months and patients on 5α-reductase inhibitors or on urethral catheter were excluded. Results: Of the 4702 patients evaluated, 70.9 per cent had PSA of less than 4 ng/ml and 29.1 per cent had PSA of more than 4 ng/ml. Of these, 875 men with a mean age of 65.72±7.4 (range 50-75 yr) had trans rectal ultrasonography (TRUS) guided biopsy. Twenty five men had biopsy at PSA level of <4 ng/ml due to positive DRE, 263 at 4.1-10ng/ml, 156 at 10.1-20 ng/ml and 431 at >20 ng/ml. Positive predictive value of PSA in ranges of 4.1-10, 10.1-20, >20 ng/ml was 15.2, 24 and 62.6 per cent, respectively with negative DRE. PSA cut-off to do biopsy was derived by ROC curve as 5.82 ng/ml for all the men. When the subjects were further stratified on the basis of DRE findings, a cut-off of 5.4 ng/ml was derived in men with normal DRE. Interpretation & conclusions: A cut-off for biopsy in symptomatic men with negative DRE could safely be raised to 5.4 ng/ml, which could avoid subjecting 10 per cent of men to undergo unnecessary biopsy.

Polymorphism of GSTM1 and GSTT1 genes in prostate cancer: a study from North India.

BACKGROUND: Glutathione-S-transferases (GSTs) are active in the detoxification of wide variety of endogenous or exogenous carcinogens. The genetic polymorphisms of GSTM1 and GSTT1 genes have been studied earlier to evaluate the relative risk of various cancers. AIM, SETTING AND DESIGN: In the present study, we examined the association of the GSTM1 and GSTT1 gene polymorphisms with sporadic prostate cancer patients in north Indian population. MATERIAL AND METHODS: This case control study was undertaken over a period of 24 months and included 103 prostate cancer patients and 117 controls; both patients and controls originated from northern part of India. The GSTT1 and GSTM1 genotypes were identified by multiplex PCR in peripheral blood DNA samples. STATISTICAL ANALYSIS: Difference in genotype prevalence and association between case and control group were assessed by the Chi square and Fisher Exact tests. RESULTS: Frequencies of null genotypes in GSTT1 and GSTM1, was 11% (13/117) and 30% (35/117) respectively in control individuals. The frequencies of GSTT1 and GSTM1 null genotypes in prostate cancer patients were 34% (35/103) and 53% (55/103) respectively. CONCLUSION: Our study demonstrates that the null genotypes of GSTT1 and GSTM1 are substantially at higher risk for prostate carcinoma as compared to the normal healthy controls. The GSTT1 and GSTM1 null genotypes did not show significant association with tobacco usage in prostate cancer patients. However, the null genotypes were significantly stratified in 50-60 year-old patients when incidence of prostate cancer is high.

Re-evaluation of reading frame-shift hypothesis in Duchenne and Becker muscular dystrophy.

The reading frame hypothesis has been proposed to explain the molecular basis of two allelic forms of muscular dystrophies, Duchenne/Becker muscular dystrophy (D/BMD). To evaluate the hypothesis in Indian D/BMD patients, we analyzed deletion of dystrophin exons in 147 DMD and 19 BMD patients. Our studies showed deviation of more than 30% from the reading frame hypothesis in DMD patients (47/147). The present results implicate a need to reevaluate the reading frame hypothesis.

Study of vitamin-D receptor (VDR) gene start codon polymorphism (Fok I) in healthy individuals from North India.

The vitamin D receptor (VDR) gene Fok I polymorphism represents a strong positional candidate susceptibility gene for different diseases like Prostate cancer, Urolithiasis, Inflammatory bowl disease and Osteoporosis. This genetic variation has also been of great interest due to its possible association with polygenic diseases. Allelic frequencies of the F/f start codon polymorphism of VDR gene vary among populations but there is no data regarding its distribution from India. The present study was carried out to determine the normal distribution of VDR gene Fok I polymorphism by using a PCR-based restriction analysis in unrelated normal healthy individuals from North India. We obtained an allelic frequency of 71.5% and 28.5% for (F) and (f) allele and the percentage of genotypes FF, Ff and ff as 46%, 51% and 3% respectively. Our results suggest that the frequency and distribution of this polymorphism in Indian population is substantially different from other populations and ethenic groups.

Genetics of gallstone disease.

Gallstone disease is a complex disorder where both environmental and genetic factors contribute towards susceptibility to the disease. Epidemiological and family studies suggest a strong genetic component in the causation of this disease. Several genetically derived phenotypes in the population are responsible for variations in lipoprotein types, which in turn affect the amount of cholesterol available in the gall bladder. The genetic polymorphisms in various genes for apo E, apo B, apo A1, LDL receptor, cholesteryl ester transfer and LDL receptor-associated protein have been implicated in gallstone formation. However, presently available information on genetic differences is not able to account for a large number of gallstone patients. The molecular studies in the animal models have not only confirmed the present paradigm of gallstone formation but also helped in identification of novel genes in humans, which might play an important role in pathogenesis of the disease. Precise understanding of such genes and their molecular mechanisms may provide the basis of new targets for rational drug designs and dietary interventions.

Carrier detection in non-deletional Duchenne/Becker muscular dystrophy families using polymorphic dinucleotide (CA) repeat loci of dystrophin gene.

BACKGROUND & OBJECTIVES: Carrier detection and prenatal diagnosis is of great importance for families with one or more sons affected with Duchenne/Becker muscular dystrophy (D/BMD). In about 35-40 per cent of these patients, the causative mutation does not involve gross rearrangement in the structure of dystrophin gene. In these non-deletional families, genetic counselling can be provided only by linkage analysis. The aim of the present study was to determine the carrier status of female relatives in north Indian families with non-deletional D/BMD using highly polymorphic intragenic dinucleotide (CA) repeat markers. METHODS: Six short tandem repeats (STRs) spanning 5' (1), central (4) and 3' regions of the dystrophin gene were used to analyse 14 unrelated families comprising 68 individuals with 12 female siblings at risk of being carriers. RESULTS: Five female siblings inherited at risk STR haplotype, six inherited normal haplotype and one had meiotic recombination. The intragenic recombinations were observed in three families at the central region STR loci and in one family between the proximal and central regions of the gene. INTERPRETATION & CONCLUSIONS: Our study suggested that at least 6 STR markers spanning 5', central and 3' regions of the dystrophin gene are essential to ascertain one or more informative loci and to rule out recombinations in non-deletional D/BMD families for carrier analysis.

Genotype-phenotype correlation in Duchenne/Becker muscular dystrophy patients seen at Lucknow.

The molecular basis of two allelic forms of muscular dystrophy, Duchenne (DMD) and Becker (BMD), has been explained by frame shift hypothesis. In order to test this hypothesis, deletional mutations in 59 patients confirmed to have DMD and 11 BMD patients were analysed using multiplex polymerase chain reaction and Southern hybridization with dystrophin cDNA probes. Translational reading frame of the dystrophin gene was derived from 'Border type' analysis of exons flanking the intragenic deletions. The correlation between genotype (reading frame) and phenotype (clinical severity) showed higher number of DMD patients (approximately 20%) deviating from the frame shift hypothesis. The patients who deviated had deletions at the central hot spot region of the dystrophin gene. The presence of these deviations in a large number of DMD patients highlights the difficulties in predicting the clinical progression of the disease based only on DNA profile.

Detection of gene deletion in patients of Duchenne muscular dystrophy/Becker muscular dystrophy using polymerase chain reaction.

Polymerase chain reaction (PCR) was used to study the presence of gene deletion (the most prominent type of mutations) in some families afflicted by Duchenne muscular dystrophy/Becker muscular dystrophy (DMD/BMD). The results clearly demonstrate deletion in the central part of the DMD gene in two of the three families studied. This information can be useful for genetic counselling with particular reference to prenatal diagnosis and carrier analysis.