Immunohistochemical characterization of tumor liberated particles (TLP) expression pattern in lung cancer.

The role of serum tumor markers in lung cancer has not been defined. It is widely believed that almost all neoplasms produce at least a few substances, but the identity of most of the known substances has not been correlated with a positive role in either the diagnosis or prognosis of patients with these neoplasms. We observed a significant immunogenic response after injecting patients with an antigen extracted from tumor-liberated particles (TLP). A specific ELISA test for TLP performed on sera from patients with lung cancer was reported recently. Based on this information, we developed a polyclonal antibody anti-TLP and screened several cell lines and tumor specimens. We concluded that TLP is a cytoplasmatic antigen specific for epithelial derived neoplasms because it was not detected in non neoplastic tissue cells, in neuroendocrine-tumors or in mesenchymal-derived tumors and normal cells. In addition, the finding that TLP is detectable in neoplasms and tumoral cell lines with common embryologic features seems to suggest that TLP might be an "oncofetal antigen". However, these preliminary observations need confirmation by additional studies using larger numbers of patients and tumor types.