Expression of CEA and trophoblastic cell markers by lung carcinoma in association with histological characteristics and serum marker levels.

The study of tumour markers in lung cancer has focused mainly on serum-based analysis. The controversy about carcinoembryonic antigen (CEA), pregnancy specific glycoprotein 1 (SP1) and beta human chorionic gonadotropin (betahCG) production in lung carcinoma has been reported in several studies. The aims of this study were: to explore an expression of CEA, SP1 and betahCG in various histological types of lung carcinoma with respect to the grade of differentiation; and to define the relationship between tumour marker expression and serum marker concentration. Ninety two lung tumours (75 non-small cell carcinomas (NSCLC) and 17 small cell lung carcinomas (SCLC)) entered the study. Tumour marker expression was compared with the serum levels of CEA, SP1 and betahCG in 57 patients (pts) with NSCLC and four pts with SCLC. Positive immunostaining of CEA and SP1 was observed in 87% NSCLC, and betahCG was found in 24% NSCLC. In the SCLC group positive staining showed in 29% of tumours, SP1 in 51% and betahCG in 18%. Positive CEA expression ranged from 50-100% within the carcinomatous cell population (pcp) and was more characteristic for well and moderately differentiated adenocarcinomas. This finding was in contrast to squamous cell carcinomas, where the majority of tumours expressed CEA in 1-50% pcp. A significant negative correlation was noticed for adenocarcinoma between tumour expression and grade of histological differentiation for CEA (P < 0.001) and SP1 (P = 0.023). Results were not significant for squamous carcinoma. Significant differences of serum CEA concentration were noticed between adenocarcinoma and squamous carcinoma (P = 0.003). In addition, a statistically significant relation was found between serum CEA concentration and an early (I + II) and advanced (IIIa + IIIb + IV) stage of NSCLC (P = 0.031). A significant correlation was noticed when serum CEA and tumour CEA expression was compared for NSCLC (P < 0.001), and for serum betahCG and tumour betahCG (P = 0.019).