DNA ploidy patterns of minute carcinomas in the stomach

DNA ploidy patterns of minute carcinomas in the stomach were determined by cytofluorometric measurement, using paraffin sections which had been prepared for histological examination. The examples studied were 19 minute carcinomas less than 5 mm in diameter, of which 12 were adenocarcinomas, and 7 were signet ring cell carcinomas. By measuring the fluorescence intensity of more than 30 mitotic nuclei, the DNA ploidy pattern of each tumor was determined. The control diploid DNA content was obtained by measuring the fluorescence intensity of non-cancerous mitoses in the gastric mucosa. In the present study, heteroploidy was seen in 5 carcinomas; 4 adenocarcinomas and one signet ring cell carcinoma. The remaining 14 carcinomas were composed of a diploid stem cell line. In 3 adenocarcinomas, polyploid cells were seen. The occurrence of heteroploidy in the minute cancers was similar to that found in advanced cancers, whereas polyploid cells appeared to occur less frequently in the minute cancers than in the advanced cancers.