A flow cytometric analysis of DNA content in primary and metastatic lesions of esophageal squamous cell carcinoma

Background. DNA content of malignant tumors has been considered a significant prognostic factor, but intra‐tumor variations in DNA content and differences in DNA content between primary and metastatic lesions have been found in various tumors. Methods. DNA indexes of multiple samples obtained from different sites in each tumor were determined by flow cytometry (FCM) in 27 esophageal squamous cell carcinomas. Results. Intratumor variation in DNA indexes in primary lesions was found in 10 (37%) of the 27 specimens. Of the rest, all DNA indexes were diploid in 5 and all identically aneuploid in 12 samples. A DNA index differing from that of the metastatic lesion was found in four (50%) of eight primary lesions; however, a component of the DNA index identical to that of metastatic lesion was found in seven (88%) of eight primary lesions. Conclusions. Recurrence after a “curative” operation was frequent in patients with a tumor that had an aneuploid DNA index, with or without a variation in DNA indexes. There was no recurrence in the five patients with tumors that had only a diploid DNA index. These results suggest that differences in DNA content between primary and metastatic lesions reflect intratumor variation in DNA content in the primary lesions. The presence of a tumor cell population with an aneuploid DNA content, even when the DNA content varied in the primary lesion, may indicate an aggressive clinical course in patients with esophageal squamous cell carcinoma.