Patients Appears to Be Dependent on the Type of Development of Antibodies against p53 in Lung Cancer

Using ¡mmunoblottingtechniques we studied the sera from small cell lung cancer and non-small cell lung cancer patients for antibodies di rected against p53. We have also characterized the majority of these patients' tumors for p53 mutations. In the sera of 13% of the patients (4 of 40 small cell lung cancer and 2 of 6 non-small cell lung cancer) we found antibodies specific for tin/>5.ftumor suppressor gene product. All of the antibody-positive patients tested had /»5.Î missense mutations and expressed detectable p53 antigen in their tumor cell lines. No anti-p53 antibodies were detected in sera from patients whose tumor had p53 stop, splice/stop, splice, or frameshift mutations (n = 10). Thus, while we find that the ability of lung cancer patients to develop anti-p53 antibodies is correlated with the type of p53 mutation, many patients have tumors with missense p53 mutations and did not develop anti-p53 antibodies. The presence of p53 antibodies was not correlated to stage, prior treatment, sex, or survival. None of these lung cancer patient sera had measurable amounts of p53 antigen. By immunoblotting all six anti-pS3 antisera we were able to detect a variety of mutant p53 proteins (including those from antibody-negative patients) and detected wild-type p53 protein. The development of anti-p53 antibodies represents an in teresting model system for studying immune responses in cancer pa tients against mutant oncogene products.