Squamous metaplasia expression of proto-oncogenes and P 53 in lung cancer patients.

BACKGROUND

The question of whether bronchial squamous metaplasia is a true preneoplasia is important and demonstrated in animal for several carcinogens. We have now approached this problem in humans and in vivo.

EXPERIMENTAL DESIGN

Squamous metaplasia in the close vicinity of surgically resected lung tumors were evaluated for their mitotic index and screened for proto-oncogenes and P 53 protein expression by immunohistochemistry and/or in situ hybridization.

RESULTS

Among 16 patients, 4 had squamous metaplasia positive for either myc messages and/or for P 53 protein accumulation. In the same patients (3/4), the autologous bronchial tumors were also positive for the same markers. Squamous metaplasia positivity was observed essentially in patients with advanced diseases and only in squamous cell carcinomas. In addition, when evaluated with 5 iodo-2'-deoxyuridine systemic infusion, all patients presented hyperproliferative basal squamous metaplasic cells.

CONCLUSIONS

These results are reminiscent of the typical preneoplastic changes observed in familial colic adenomatosis, where genetic changes accumulate in hyperproliferative cells. They also suggest that bronchial squamous metaplasia could be an authentic preneoplasia in, at least, squamous cell carcinomas.