Polymorphism of p53 gene in Jordanian population and possible associations with breast cancer and lung adenocarcinoma

OBJECTIVE: To determine the prevalence of 3 polymorphisms in p53 gene in 3 healthy Jordanian groups and 2 cancer patient groups.

METHODS: Genomic DNA was extracted from blood samples obtained from 84 cancer patients (breast and lung adenocarcinoma) and 136 healthy subjects (representing Jordanian general population, Bedouins and Charkas). Samples were collected from Al-Amal Hospital for Cancer, Amman and from health centers located in different regions of Jordan from March 2002 to October 2002. Polymerase chain reaction (PCR) was used to amplify intron 3, exon 4 and intron 6 and PCR products were analyzed using gel electrophoresis and BstUI and MspI analysis. Allele frequencies (A1) were estimated for the 3 polymorphisms and Chi-square (X2) test was used to determine the significance of differences from the Hardy-Weinberg equilibrium.

RESULTS: Differences in allele frequencies for all 3 polymorphisms were observed among the various groups. Analysis based on haplotype frequencies showed that MspI A2 allele linked to BstUI allele was associated with lung adenocarcinoma, whereas the loss of the 16-bp duplication allele in combination with MspI A2 allele was associated with breast cancer. In the cancer patients, the most frequent extended haplotype was the absence of the 16-bp duplication in combination with the presence of the BstUI A2 and MspI restriction sites.

CONCLUSION: No significant difference was found with respect to the BstUI polymorphism between cancer patients and healthy groups. However, a significant difference was found with respect to the MspI polymorphism between lung adenocarcinoma patients and healthy Jordanian general population. Charkas have a higher cancer risk than Jordanian general population based on the (16bp A1-MspI A2) for breast cancer and (MspI A2-BstUI A2) for lung adenocarcinoma.