Correlation between DNA ploidy and clinical features in smooth muscle tumors of the gastrointestinal tract.

Paraffin-embedded tissue samples from 51 surgically resected, gastrointestinal smooth muscle tumors (10 leiomyomas, 5 leiomyoblastomas and 36 leiomyosarcomas) were assayed for nuclear DNA content, and the results were examined for correlation with clinico-pathological variables (tumor size, cellularity and mitosis) and prognosis. Twenty-four (47%) of the 51 tumors, consisting of 3 (30%) of the 10 leiomyomas, 2 (40%) of the 5 leiomyoblastomas and 19 (53%) of the 36 leiomyosarcomas, were identified as aneuploid. A close correlation was found between the mitotic index and the tumor size (<cc> = 0.528; P < 0.001). The DNA ploidy pattern of the leiomyosarcoma was closely correlated with the patient survival periods (P = 0.06). The estimated median survival period was 73 months for patients with diploid tumors, and 51 months for those with aneuploid tumors. The 10-year survival rate for aneuploid tumors was lower than that for diploid tumors (P < 0.001). The measurement of DNA content may provide an index of prognostic value in gastrointestinal leiomyosarcomas.