Limitations of the clonal agar assay for the assessment of primary human ovarian tumour biopsies

Abstract

Summary.-114 biopsy specimens from 70 patients with ovarian carcinoma at all stages of disease were submitted for assessment of clonogenic capacity in agar. A highly significant correlation was found between agar clonogenicity and patient survival after biopsy. However, problems related to inherent tumour heterogeneity, quality of sample and tissue disaggregation indicate that this technique may have limited applicability in the routine assessment of patients. Only 41 biopsy specimens (36%) from 31 patients (44.3%o) complied with the prerequisite criteria for agar clonogenic assessment, namely: (a) the confirmed presence of malignant cells in the biopsy, (b) the ability to prepare a single-cell suspension, and (c) adequate viable cell numbers for assay. Furthermore, although the dominant patterns of agar clonogenic growth could be identified and correlated with stage of disease, the heterogeneity in both initial clonogenic capacity and "self-renewal" capacity assessed by the ability of primary clones to propagate in liquid culture and reclone in agar was too inconsistent for the assay to be used as a prognostic index for the individual patient.

Ovarian carcinoma cells in culture: Assessment of drug sensitivity by clonogenic assay

“…Our culture success rates are superior to those of Williams et al (1983) but in common with these and other workers, we have reservations about the low plating efficiencies associated with this method (Bertoncello et al, 1982;Rupniak & Hill, 1980). As a consequence of this, too few samples are evaluable for drug study.…”

“…Similarly, small sample size is a problem which has greater implications for the production of drug results than is true for assays which depend on the establishment of monolayers, since the number of cells derived at the outset determines the number of tests which may be made (Bertoncello et al, 1982). Samples from "first" laparotomies are often generous, but it is at "second-look" laparotomies or the tapping of effusions from patients who have progressed, that the provision of samples large enough for drug testing for possible second-line chemotherapy is vital.…”

Chemosensitivity testing of human lung cancer cell lines using the MTT assay

“…(Bertoncello et al, 1982;Selby et al, 1983). Currently, the limiting feature of this assay is data analysis that obviously requires the use of appropriate computer software, which is now becoming generally available.…”

“…For any given tumour cell line the optical density of the solubilized formazan product obtained after incubating tumour cells with MTT is directly proportional, over a large range, to the number of cells per well (Carmichael et al, 1987a), making the assay directly comparable with assays counting the total number of cells in the culture before and after a treatment. This assay also has the advantage that it can be used on virtually all human lung cancer cell lines, including those difficult to assay using clonogenicity as the end-point because of low cloning efficiencies, and/or difficulty in preparing viable single cell suspensions (Bertoncello et al, 1982;Selby et al, 1983). Finally, the Division of Cancer Treatment, National Cancer Institute, USA, is currently evaluating this assay using panels of human tumour cell lines to screen for new drugs.…”

Hormone supplemented media for cloning human breast cancer: Increased colony formation without alteration of chemosensitivity

“…However, the success of the commonly used in vitro assays requires the ability to clone human tumours in semi-solid medium with a colony forming efficiency (CFE) sufficiently high to permit accurate analysis. At the present time, with standard culture techniques, the CFE of most fresh tumour specimens, including breast carcinoma, varies from 0.001-0.3%, permitting in vitro drug testing in only 20-35% of all specimens (Carney et al, 1981a, Bertoncello et al, 1982Pavelic et al, 1980;Rupniak & Hill, 1980;Sandbach et al, 1982).…”