Serum amyloid A in carcinoma of the lung.

Serum concentrations of serum amyloid A protein (SAA), peripheral blood lymphocytes (PBL) mitogenic response to phytohemagglutinin (PHA) and Concanavalin A (Con A), numbers of circulating T- and B-lymphocytes and length of survival after diagnosis were measured in 50 patients with cancer of the lung. SAA levels were significantly elevated when compared to 50 control subjects (P less than 0.001), but did not correlate with state of tumor spread at the time of diagnosis. Mitogenic responses of PBL from the cancer patients to PHA and Con A were significantly depressed (P less than 0.001), but also did not predict state of metastatic spread. The percentage of circulating T-lymphocytes was also significantly depressed in cancer patients when compared to controls. In six patients who survived tumor-free for greater than 2.5 years, SAA serum concentrations returned to normal. Statistical analysis showed a significant correlation between SAA serum concentrations and PBL mitogenic response to Con A. In addition, both high SAA concentrations and depressed PBL responses to Con A correlated with shortened survival. Therefore, these parameters may be of value in evaluating prognosis in patients with lung cancer. In addition, serial monitoring of SAA concentrations may be of value in evaluating recurrence or cure of lung cancer.