Clonogenic in vitro growth and histologic grading of primary human breast tumors

Lack of association between in vitro clonogenic growth of human cervical carcinoma and tumour stage, differentiation, patient age, host cell infiltration or patient survival

Biopsies from 117 patients with cervical carcinoma were studied using a clonogenic assay to assess in vitro growth. Successful colony growth was achieved in 84 tumours (72%) with a mean colony-forming efficiency (CFE), based on total viable nucleated cell counts, of 0.18 +/- 0.49% (+/- 1 standard deviation). There was a wide range of values, from 0.003-4.28%, with a coefficient of variation of 272%. The relationship between clinical features of cervical carcinoma and in vitro colony formation was investigated. No significant association was demonstrated between in vitro growth and either clinical stage (r = 0.02), tumour differentiation (r = -0.08) or patient age (r = -0.12). There was no significant difference in tumour grade between the group of tumours which failed to grow in culture and those which grew well (p = 0.70). In addition, there was no correlation between CFE and the degree of macrophage (r = 0.001), lymphocyte (r = 0.12), or granulocyte (r = 0.08) infiltration. There was no significant difference between CFEs of tumours from patients who had died and from those who were alive and well after a minimum of 2 years' follow-up after radiotherapy (p = 0.51). Ability to form colonies in agar was not associated with a worse prognosis (p = 0.49). Although CFE is an independent biological parameter, our results suggest that, for cervical carcinoma, it is not useful as a univariate prognostic factor.

Human tumor cloning assays: applications in clinical oncology and new antineoplastic agent development

The human tumor cloning assay (HTCA) has been available for preclinical and clinical applications for the last 11 years. This article examines the usefulness of that assay both in the practice of clinical oncology and in the development of new antineoplastic agents. In the area of prediction of response of an individual patient's tumor to a particular antineoplastic agent, in a total of 2274 correlations in a variety of clinical trials, the assay has shown a remarkably good ability to predict whether a patient's tumor would respond to a particular agent (percent true positives 69%; percent true negatives 91%). However, despite this ability to predict these responses, the assay has not yet been accepted for general clinical use, because there have not been rigorous trials to prove the assay will improve patient survival. These rigorous clinical trials are now underway. In the area of drug development, the HTCA has been used to screen for new antineoplastic agents as well as to pinpoint tumor types against which the new agent will be active in phase II clinical trials. As will be seen in this review, the HTCA has been most successful in this area.

Chemoresistance is not a cause of the apparent failure of adjuvant chemotherapy in postmenopausal women

Chemotherapeutic regimens used for the adjuvant treatment of breast carcinoma are less effective when applied to postmenopausal women than when applied to premenopausal women. Differences in growth fraction or altered chemosensitivity of tumors are potential causes of the differential effects of chemotherapy in younger and older patients. We have attempted to identify the presence of these putative causes by measuring size of clonogenic cell fraction and drug sensitivity of progenitor cells on the tumors from pre- and postmenopausal women. We found that the chemosensitivity of tumors was similar for patients of all ages. We further observed that the clonogenic cell fraction of tumors from women older than 65 years tended to be smaller compared to those of all other patients, while the hormone-sensitivity of tumors from these patients was higher. Our observations thus suggest that drug resistance related to inherent metabolic characteristics of tumor cells may not be a major contributing cause of failure of adjuvant chemotherapy in the treatment of postmenopausal women.

Effects and interactions of epidermal growth factor, insulin, hydrocortisone, and estradiol on the cloning of human tumor cells

We investigated the effects and interactions of epidermal growth factor (EGF), insulin, hydrocortisone, and estradiol on the growth of 18 freshly obtained human tumors in our human tumor stem cell assay (HTSCA) cultured at a reduced serum concentration (8.5% ml). All possible combinations of these four supplement factors were added to the assay to determine the ability of each component to enhance colony formation. We found that hydrocortisone was the most effective single supplement in stimulating colony growth in the HTSCA. Supplementation with insulin, estradiol, or both had some growth-promoting effect but not as great as hydrocortisone. Moreover, the addition of insulin, estradiol, or both often demonstrated a negative interaction with hydrocortisone. EGF supplementation alone; in dual combination with insulin, estradiol, or hydrocortisone; or in combination with estradiol and insulin in the assay did not significantly increase colony formation. However, EGF added to the cultures containing hydrocortisone with insulin and/or estradiol significantly increased colony formation and reversed the negative effect of insulin and estradiol on hydrocortisone activity. Thus, under conditions of our assay, the most effective combination in promoting colony growth contained all four factors.