Contribution of cyclin D1 (CCND1) and E-cadherin (CDH1) alterations to colorectal cancer susceptibility: a case-control study.

Cyclin D1 (CCND1) and E-cadherin (CDH1) are two important genes of the ß-catenin/LEF pathway that is involved in tumorigenesis of various cancers including colorectal cancer (CRC). However, studies of the association between genetic variants of these two genes and CRC have shown conflicting results. We conducted a genetic association study in South Indian population (cases, 103; controls, 107) to assess the association of CCND1 870G/A and CDH1 -160C/A single nucleotide polymorphisms (SNPs) with CRC risk. Genotyping of SNPs was performed by PCR sequencing analysis. Haplotype frequencies for multiple loci and the standardized disequilibrium coefficient (D') for pair-wise linkage disequilibrium (LD) were assessed by Haploview Software. In addition, to better understand the role of CCND1 and CDH1 in the pathophysiology of CRC, the expression pattern was evaluated in analogous tumor and adjacent normal tissues from 23 CRC patients by Western blot analysis. The frequencies of CCND1 870A/A (P = 0.045) genotype, CDH1 -160A allele (P = 0.042), and 870A/-160A haplotype (P = 0.002) were significantly higher in patients as compared with controls. Strong LD was observed between 870G/A and -160C/A SNPs in cases (D' = 0.76) as compared to controls (D' = 0.32). Furthermore, elevated CCND1 and diminished CDH1 expression was observed in tumor tissue as compared with analogous normal tissue of CRC patients. Interestingly, advanced-stage tumors showed wider expression alterations than in early-stage tumors. In conclusion, CCND1 870G/A and CDH1 -160C/A SNPs may modify the risk of CRC susceptibility in South Indian population. In addition, elevated CCND1 and diminished CDH1 expression appears to be useful prognostic markers for CRC.

TP53 alterations and colorectal cancer predisposition in south Indian population: a case-control study.

The objective of the present study was to investigate the association between TP53 gene single nucleotide polymorphisms (SNPs) and colorectal cancer (CRC) predisposition in south Indian population and to evaluate the role of TP53 expression in the pathophysiology of CRC. A genetic association study was conducted in 103 CRC cases and 107 controls of south Indian origin. We genotyped ten selected TP53 SNPs by polymerase chain reaction-sequencing analysis. Haplotype frequencies for multiple loci and the standardized disequilibrium coefficient (D') for pairwise linkage disequilibrium (LD) were assessed by Haploview Software. In addition, to better understand the role of TP53 in the pathophysiology of CRC, the expression pattern was evaluated in analogous tumor and normal tissues from 23 CRC patients by Western blot analysis. The frequencies of Pro72Pro (P = 0.0033) genotype and Ser47/Pro72 (P = 0.00171) haplotype were significantly higher in patients as compared to controls. Strong LD was observed between codon 47 and 72 in cases (D' = 0.32) as compared to controls (D' = 0.21). The polymorphism was not observe at the remaining eight SNPs loci analyzed. Furthermore, increased TP53 expression was observed in tumor tissue than in analogous normal tissue of CRC patients. Interestingly, advanced stage tumors showed more elevated TP53 expression compared to early stage tumors. In conclusion, the TP53 Pro72Pro genotype and Ser47/Pro72 haplotype has an increased risk for CRC predisposition in south Indian population. In addition, elevated TP53 expression appears to be useful prognostic marker for CRC.

Mitochondrial genome variations in advanced stage breast cancer: a case-control study.

Entire mitochondrial DNA (mtDNA) sequencing was carried out in 101 primary breast cancer patients and 90 controls of south Indian origin. We identified 69 novel mutations in breast cancer patients and 637 reported polymorphisms in patients and/or controls. PolyPhen-2 analysis predicted 5 out of 14 novel missense mutations as 'probably damaging variants'. Haplogrouping analysis identified a significant association between haplogroup M5 and breast cancer risk. Microsatellite instability and tumor specific large scale mtDNA deletions were not observed in tumor tissues from the patients. In conclusion, mtDNA mutations and haplogroups may constitute an inheritable risk factor for pathogenesis of breast cancer.

Association of E-cadherin single-nucleotide polymorphisms with the increased risk of breast cancer: a study in South Indian women.

BACKGROUND: E-cadherin (CDH1) plays an important role in intercellular adhesion, cell signaling, and cellular differentiation. Association of single-nucleotide polymorphisms (SNPs) of CDH1 has been identified in a number of epithelial malignancies; however, studies related to breast cancer are very few. AIM: To investigate the association between CDH1 SNPs and breast cancer risk in south Indian women. METHODS: Genotyping of CDH1 functional SNPs (-347G/GA, -160C/A, and +54C/T) was carried out on genomic DNA of blood from breast cancer patients (n=202) and controls (n=250) of south Indian origin by PCR-sequencing and PCR-restriction fragment length polymorphism techniques. Haplotype frequencies for multiple loci and the standardized disequilibrium coefficient (D') for pairwise linkage disequilibrium (LD) were assessed by Haploview Software. RESULTS: The frequencies of -160A/A genotypes (p=0.038) and -160A alleles (p=0.046) were significantly higher in patients compared to controls. In addition, the frequency of the -347GA/-160A/+54C haplotype was also significantly elevated in patients (p=0.0238). Strong LD was observed between -347G/GA and +54C/T loci (D'=0.44) in patients compared to controls. CONCLUSION: The CDH1 -160C/A polymorphism may constitute an inheritable risk factor for breast cancer in south Indian women.