[Study on the relationship of alteration and expression of p16 gene to pancreatic carcinoma].

OBJECTIVE

To directly investigate the effect of genetic alteration(homozygous deletion and point mutation) and expression of p16 gene on pancreatic carcinomas.

METHODS

Thirty-five cases were analyzed for genetic alteration and expression of p16 gene by polymerase chain reaction(PCR), single strand conformation polymorphism(SSCP), DNA sequencing and immunohistochemical method.

RESULTS

The analysis of pancreatic carcinoma for p16 gene revealed alteration in 19 of 35 cases, among which 12 pancreatic carcinomas had 522 bp homozygous deletion at least and 7 cases had two point mutations at the same site. One of them is 126th codon GTC --> AAT (Val126Asn); the other is 127th codon GCA --> GCG (A127A). The 3D (three-dimensional) structure of P16 protein determined by computer techniques according to PDB indicated that Val126Asn influenced the space structure of P16 protein and affected the function of P16 protein. Twelve cases revealed no P16 protein and 9 cases showed low level expression of P16 protein.

CONCLUSION

The alteration of p16 gene and abnormal expression of P16 protein are significantly correlated with the biological behavior and clinical staging of pancreatic carcinoma and may hence be helpful to prognostication