[Quantitation of Ras p21 oncogene and DNA content of gastrointestinal smooth muscle tumors and prognostic significance].

Expression of ras p21 oncogene and DNA content of paraffin-embedded tissues from 55 smooth muscle tumors of the gastrointestinal tract were analysed simultaneously by using immunofluorescence and flow cytometry. All of 14 leiomyomas were found to be DNA diploid and lower-expression of ras p21. Four cases of DNA aneuploidy (33%) and 9 cases of ras p21 overexpression (75%) were found in 12 potential malignant smooth muscle tumors, while all 29 cases of leiomyosarcomas were aneuploidy (100%) (P < 0.005), but the rate of ras p21 overexpression was not increased continuously (72%) (P < 0.005). 24 of 33 aneuploid tumors (73%) were found to be ras p21 overexpression, while in 22 diploid tumors, there were only 6 cases (27%) (P < 0.005). The outcome of the patients with ras p21 lower-expressed diploid tumor was excellent, compared to the patients with ras p21 overexpressed aneuploid tumor it was worst (P < 0.005). It was suggested that DNA aneuploidy and ras p21 overexpression could be regarded as the mark of malignancy. The overexpression of ras p21 oncogene was always presented in the early stage of malignant smooth muscle tumors, when the cell proliferation was active but the DNA content was still normal, and stable in the whole procss of the tumor progression. ras p21 expression and DNA content could supply a deficiency each other in the diagnosis and could be used as objective parameters in distinguishing malignancy from benign and predicting the prognosis of the patients with smooth muscle tumors of the gastrointestinal tract.