Rearrangement in the Coding and 5′ Region of P53 Gene in Human Oral Tumors

Different postreplicative, transcriptional, and translational mechanisms responsible for p53 gene inactivation are slowly unfolding. Rearrangement of the p53 gene is a very rare event in human solid tumors and has been reported only in osteosarcomas. From our laboratory we have recently reported rearrangement only in the coding region of the p53 gene in breast tumors. In this report we have undertaken a systemic investigation of p53 in oral tumors. Results have shown rearrangement in the coding region of p53 in 20% of cases and in the 5′ region of p53 gene in 8% of cases. No allelic loss and amplification of p53 gene was observed in these tumor samples. In our earlier studies on breast tumors, we found no abnormality in the 5′ region of p53. However, in the present study we report for the first time rearrangement in the 5′ region of p53 in oral tumors. Correlation of p53 gene rearrangement with p53 expression of RNA and protein indicates that rearrangement in the 5′ region of p53 might not have a role in p53 expression. However, rearrangement in the coding region of p53 might play a critical role in controlling p53 gene activity in the process of tumorigenesis.