Relationship of DNA ploidy to chemoresistance of tumors as measured by in vitro tests

To examine whether patients with aneuploid tumors might derive more benefit from chemotherapy than would patients with diploid tumors, predictive tests for determining resistance in human tumors were carried out and the test results compared with the DNA ploidy of the corresponding tumors. Multidrug-resistance in 15 kidney carcinomas grown as primary cultures was determined by immunofluorescence by Mab C219, which is specific for the plasma membrane glyco-protein P-170, and by the use of tritiated nucleotide incorporation after addition of doxorubicin. Aneuploid tumors had a higher tendency to be more sensitive than diploid tumors, but the correlation was not significant. This was confirmed by reanalyzing our earlier data on ovarian and lung cancers. In conclusion, DNA measurement using flow cytometry does not appear to be a suitable tool for prediction of resistance of human tumors to chemotherapy.