THE PROGNOSTIC APPLICATION OF CYTOKERATIN TYPING OF NONSMALL CELL LUNG-CARCINOMA - A RETROSPECTIVE STUDY

BACKGROUND. In a previous study, the authors used a variety of anticyt okeratin monoclonal antibodies to show that a large proportion of lung tuners cytologically diagnosed as squamous cell carcinoma contain cel ls expressing simple epithelial cytokeratins, suggesting that these tu mors have their origin in adenocarcinoma, These findings raised the po ssibility that cytokeratin (CK) typing might have a diagnostic capacit y not attainable by standard histopathology, The aim of the current st udy was to assess the value of CK typing for this purpose by determini ng the correlation between the diagnosis of lung tumors based on CK ty ping and the survival rate of the patients. METHODS, Paraffin embedded tissue sections of 66 nonsmall cell lung carcinoma (NSCLC) specimens were examined. These included 18 adenocarcinomas, 32 squamous cell car cinomas, and 16 undifferentiated carcinomas, all diagnosed surgically and histopathologically, and further classified as either Stage I or I I, CK typing was performed using the streptavidin-biotin-peroxidase me thod, employing the following anti-CK monoclonal antibodies: Ks.B.17 ( which reacts with CK 18), A3-3 (which reacts with CK 13), and E5-9 (wh ich reacts with CK 10). RESULTS, Comparison between the 5-year surviva l rates (5 ysr) of patients with different NSCLC indicated that all ty pes of Stage II tumors had a much poorer prognosis than Stage I tumors . Differences found in the 5 ysr among patients with different types o f Stage I tumors were not statistically. significant (adenocarcinomas, 33% 5 ysr; squamous cell carcinomas, 59% 5 ysr; undifferentiated carc inomas, 36% 5 ysr; all diagnosed by conventional histopathology), Simi larly, no significant differences were noted in 5 ysr between patients with tumors stained positively or negatively with monoclonal antibodi es A3-3 or E5-9 (anti-CK 13 and anti-CK 10, respectively). In contrast , highly significant differences (P = 0.002) were found in the 5 ysr b etween patients with Stage I tumors positively or negatively stained w ith monoclonal antibody Ks.B.17 (23% vs. 75% 5 ysr, respectively) rega rdless of the histologic types of tumors. Especially informative was a combination of immunohistochemical and histologic diagnoses, with bes t survival rates (87% 5 ysr) in Ks.B.17 negative tumors histologically diagnosed as Stage I squamous cell carcinomas and worst survival rate s (14% 5 ysr) in Ks.B.17 positive tumors diagnosed as adenocarcinomas. CONCLUSIONS. The current study showed that CK 18 typing of lung tumor s can provide a more accurate diagnosis and therefore facilitate the p lanning of more suitable therapeutic approaches. (C) 1997 American Can cer Society.