Serum epidermal growth factor receptor and p53 as predictors of lung cancer risk in the ATBC study

Serum samples from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention St udy were used in a nested case control study to identify the possible assoc iation between the serum level of epidermal growth factor receptor and p53 in respect to lung cancer. The proteins were assayed for by commercial immu noassays that showed uneven, often unacceptable, quality. For EGFR there wa s no relationship to lung cancer. Two physiological variables appeared to m odify the serum level of EGFR, age by decreasing it annually by about 4 fmo l ml(-1), and stroke by increasing it by 150 fmol ml(-1). For p53, myocardi al infarction appeared to cause an increase in serum levels of this protein . While the serum levels of p53 were only moderately increased in lung canc er patients, particularly those with squamous cell carcinoma, the intriguin g findings related to the high frequency of p53-positive patients among tho se belonging to the group of patients being treated by surgery and those be longing to clinical stages 1 and 2 as compared with higher clinical stages. An untested rationalization of these results was that patients with advanc ed lung cancer, stages 3 and higher, develop autoantibodies against the mut ant p53 and thus mask the serum levels of the mutant p53 protein.