Influence of the elimination of lymphocytes from tumor cell suspensions on the calculation of S-phase fractions by flow cytometry.
Contaminating lymphocytes were eliminated from enzymatically obtained cell suspensions of 260 surgical biopsy specimens by density gradient centrifugation using lymphocyte separation medium (LSM) in an attempt to improve the determination of S-phase fractions by flow cytometry. The elimination of lymphocytes from the cell suspensions was ascertained on cytologic smears prepared from the suspensions before and after LSM centrifugation. Following the elimination of lymphocytes, the calculated S-phase fractions increased significantly in DNA-diploid tumors, but not in DNA-aneuploid ones. The increase of the S-phase fraction was correlated to the numbers of lymphocytes in the tumor cell suspensions before LSM centrifugation. Furthermore, in 12 tumors originally classified as diploid, an aneuploid cell line was detected after LSM centrifugation. These results indicate that samples from diploid tumors containing large numbers of lymphocytes should have the lymphocytes eliminated by methods such as LSM centrifugation in order to obtain reliable results for the calculations of the S-phase fractions.
Eckhardt
R
R
Institute of Experimental Pathology, German Cancer Research Center, Heidelberg.
Feichter
G E
GE
Goerttler
K
K
D001943:Breast Neoplasms / Q000473:pathology; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D001330:Electronic Data Processing; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007399:Interphase; D007414:Intestinal Neoplasms / Q000473:pathology; D008214:Lymphocytes; D009369:Neoplasms / Q000473:pathology*; D010051:Ovarian Neoplasms / Q000473:pathology; D011003:Ploidies