p53 gene alternation in squamous cell carcinoma of the esophagus detected by PCR-cold SSCP analysis.

Mutations of the p53 tumor suppressor gene play an important role in the development of common human malignancies. Previous reports revealed that the frequencies of p53 alternations in esophageal carcinoma varied from 26% to 87%. The clinical significance of p53 alternations is still disputed. In the present study, we used polymerase chain reaction--"cold" single-strand conformation polymorphism (PCR-"cold" SSCP)--to investigate p53 genetic alternations in 63 surgical specimens of esophageal squamous cell carcinoma (ESC). Our experiments showed that the optimum buffer temperature for "cold" SSCP analysis was 14 degrees C while the PCR products were around 200-300 bp in size. Among 63 tumorous samples, p53 alternations was detected in 47 tumors, or an incidence rate of 74.6%. For nontumorous mucosal samples, the incidence of p53 alternations was 55.5% (35/63 samples). Additionally, p53 alternations occurred most frequently at exon 6 (50.8%), followed by exon 7 (33.3%), exon 8 (17.5%) and exon 5 (12.7%). Multiple genetic alternations (> or = 2 exons) between p53 exons 5-8 in the same examined samples were found in 21 (33.3%) of 63 tumors, and in 8 (12.7%) of 63 nontumorous mucosal specimens. Our results further showed that p53 alternations did not correlate with age, depth of tumor invasion, lymph node metastasis, tumor stage, cell differentiation or lymphovascular invasion in ESC (P > 0.05). Moreover, the survival rate in patients with p53 alternations was similar to that in patients without p53 alternations (P > 0.05). In conclusion, PCR-"cold" SSCP is a rapid and sensitive method for identifying p53 genetic alternations. p53 genetic alternations occur with a relatively high incidence for ESC, but p53 abnormality has no impact on prognosis.