Non-small cell lung carcinoma: morphology and DNA content

Objective: To correlate stage-related and histologic features of non-small cell lung cancer (NSCLC) with DNA flow cytometric parameters. Study design: The clinicopathologic features, DNA flow cytometric parameters (ploidy type, S-phase fraction and DNA index [DI]) of 72 surgically resected NSCLC were reviewed. Results: NSCLC were classified on the basis of their DI in diploid, peridiploid, hypotriploid, triploid, hypertriploid, tetraploid, hypertetraploid and multiploid tumors. DI was significantly related to pleural infiltration, pT, histologic type and evidence of necrosis. Tumors infiltrating the pleura were mostly triploid or hypertriploid; high pT stages were also hypertetraploid. Adenocarcinomas showed a wide DI distribution, squamous carcinomas were mostly diploid, triploid or hypertriploid and large cell carcinomas were mostly triploid, hypertriploid and hypertetraploid. The best combination of features able to predict disease relapse was pT plus pN plus grading and divergent differentiation. Conclusion: Many stage-related and histologic features are associated with particular DI classes, which vary in relation to the feature itself and, in some cases, regardless of classical methods of grading and histologic typing. DNA content analysis highlights greater biologic heterogeneity in NSCLC than evidenced morphologically.