A new tumour associated antigen of non-small cell lung cancer: tumour liberated proteins (TLP)--a possible new tumor marker.

TLP (Tumour Liberated Proteins) is a 214 kDa protein, isolated from lung cancer tissue and synthetic nonapeptide CSH-275 is a major epitope identified on a 100 kDa TLP fragment and used to create antibodies in rabbit (antiserum termed CSH-419). CSH-419 antiserum, labelled or conjugated as necessary, was used to detect TLP on sera from NSCLC patients by a new ELISA test set up as a 1 step sandwich format test. This ELISA was performed on sera from 534 individuals. TLP was detected in 53.1% of NSCLC patients, with a 0% response in patients with cancers other than NSCLC, 7.6% response in unknown blood donors, and 17.4% response in patients with chronic lung diseases correlated with an elevated risk for lung cancer. TLP was particularly present in early stages of disease: 75% in stage I, 56% in stage II and III and 45% in stage IV. The presence of TLP antigen in sera from NSCLC patients indicates that TLP could represent an useful tumour marker.