Analysis of antibodies to p16INK4A tumor suppressor gene products in lung cancer patients

We examined by immunoblotting antibodies that bind to p16(INK4A) tumor suppressor gene products in the sera of patients with lung cancer. Sera from 15 to 102 patients, including 6 with adenocarcinoma, 3 with squamous cell carcinoma, 2 with large cell carcinoma and 4 with small cell carcinoma, reacted with a glutathione-S-transferase (GST) fusion protein containing whole human anti-p16(INK4A), produced by Escherichia coli. However, sera from 30 normal volunteers did not react with the GST-p16(INK4A) fusion protein. The background such as age, gender, performance status, histology, stage, smoking history, and prior treatment was not significantly different between the patients with and without anti-GST-p16(INK4A) antibodies. Circulating p16(INK4A) tumor suppressor products were not detected in any individuals with lung cancer or in the normal controls.