Presence of antibodies against retinoblastoma tumor suppressor protein in patients with lung cancer

Retinoblastoma (RB) protein and antibody against RB protein in sera from 45 lung cancer patients and 30 healthy volunteers were examined using bacteri ally synthesized glutathione S-transferase (GST) RB fusion protein and immu noblot analysis. RB protein was not detected in sera from any individuals w ith lung cancer or in any healthy volunteers. Sera from 6 patients, includi ng 4 with non-small cell carcinoma and 2 with small cell carcinoma, reacted to a GST-RB fusion protein but not with a GST protein. Sera from 30 normal volunteers reacted to neither GST-RB fusion protein nor GST protein. The b ackgrounds such as age, gender, performance status, histology, stage, smoki ng history, and prior treatment were not significantly different between th e patients with and without anti-RB antibodies. This is the first report de scribing the presence of anti-RB antibody in patients with malignant tumors . Further studies are needed to establish clinical significance for anti-RB antibody.