NUCLEAR-DNA IN CARCINOID-TUMORS OF THE LUNG

Abstract

Fluorescence cytophotometric DNA measurements on 15 [human] carcinoid tumors generally yielded histograms with a prominent G1-phase peak and only low frequencies of S- and G2-phase nuclei. In 13 tumors the modal DNA value was near diploid (1.75-2.25). Of these 15 tumors, 3 showed a much greater number of S- and G2-phase values than the others and in 2 of them there were also G1-phase peaks below the near-diploid range. Among 22 samples of small cell carcinoma of the lung (SCCL), the modal DNA value was hypodiploid in 2, near diploid in 7 and hyperdiploid in 13. The proportion of S-hase cells was higher in the SCCL samples than in the carcinoid tumours. Nuclear DNA distribution profile may facilitate morphological discrimination of a classical pulmonary carcinoid from small cell carcinoma. In a borderline case, the findings of a hyperdiploid DNA stem line and high proliferative activity will favor the diagnosis of SCCL.