Assessment of methods for the cytogenetic analysis of human solid tumors

A comparative study was undertaken to evaluate the effectiveness of various procedures (e.g., direct harvest vs. short-term culture) for the cytogenetic analysis of human solid tumors. A total of 51 specimens (38 primary tumors, 13 effusions) were examined from 45 patients with tumors of the ovary, lung, breast, colon, and testicles. Sufficient numbers (≥3) of metaphase cells to be useful for karyotypic analysis were obtained in 42 of 51 (82.3%) specimens. More than 10 analyzable metaphases were found in each of 32 specimens (62.7%), but in some cases it was necessary to examine many slide preparations to achieve this number. The rate of successful chromosome preparations was markedly better for short-term cultures than for specimens harvested directly. Short-term cultures generally showed a mitotic peak after about 3 days of growth in vitro. Generally, the quality of metaphase cells was better in specimens disaggregated enzymatically with collagenase than in those dissociated mechanically. Exposure to ethidium bromide (EB) for the final 2 hours of culture yielded more cells with elongated chromosomes than cultures harvested by conventional methods without EB. Overall, the findings indicate that successful karyotypic analysis can be performed in a high percentage of human solid tumors with the use of techniques that can be readily applied in most cytogenetics laboratories. However, further methodological advances in tissue culture are warranted to routinely provide large numbers of mitotic cells for karyotypic analysis.