A study on p53 gene alterations in esophageal squamous cell carcinoma and their correlation to common dietary risk factors among population of the Kashmir valley.

AIM: To systematically examine the extent of correlation of risk factors, such as age, consumed dietary habit and familial predisposition with somatic Tp53 molecular lesion causal to elevate carcinogenesis severity of esophageal squamous cell carcinoma (ESCC) among the Kashmiri population of Northern India.

METHODS

All cases (n = 51) and controls (n = 150) were permanent residents of the Kashmir valley. Genetic alterations were determined in exons 5-8 of Tp53 tumor suppressor gene among 45 ESCC cases histologically confirmed by PCR-SSCP analysis. Data for individual cancer cases (n = 45) and inpatient controls (n = 150) with non-cancer disease included information on family history of cancer, thirty prevailing common dietary risk factors along with patient's age group. Correlation of genetic lesion in p53 exons to animistic data from these parameters was generated by Chi-square test to all 45 histologically confirmed ESCC cases along with healthy controls.

RESULTS

Thirty-five of 45 (77.8%) histologically characterized tumor samples had analogous somatic mutation as opposed to 1 of 45 normal sample obtained from adjacent region from the same patient showed germline mutation. The SSCP analysis demonstrated that most common p53 gene alterations were found in exon 6 (77.7%), that did not correlate with the age of the individual and clinicopathological parameters but showed significant concordance (P<0.05) with familial history of cancer (CD = 58), suggesting germline predisposition at an unknown locus, and dietary habit of consuming locally grown Brassica vegetable "Hakh" (CD = 19.5), red chillies (CD = 20.2), hot salty soda tea (CD = 2.37) and local baked bread (CD = 1.1).

CONCLUSION

Our study suggests that somatic chromosomal mutations, especially in exon 6 of Tp53 gene, among esophageal cancer patients of an ethnically homogenous population of Kashmir valley are closely related to continued exposure to various common dietary risk factors, especially hot salty tea, meat, baked bread and "Hakh", that are rich in nitrosoamines and familial cancer history.