Human Endometrial Tumors Research Articles

Aberrant FGF-2, FGF-3, FGF-4 and C-erb-B2 gene copy number in human ovarian, breast and endometrial tumours.

The important role of oncogene amplification and tumour suppressor gene deletion in human tumours is becoming increasingly apparent. However, extensive screening of human tumours is required before the prognostic significance of such genetic abnormalities can be fully appreciated. The present investigation describes a rapid non-radioactive and largely automated procedure for the analysis of aberrant gene copy number in large numbers of tissue samples of different human tumours. This procedure is based on the sequential use of the polymerase chain reaction (PCR) and high performance ion exchange liquid chromatography (HPIEX). Using this rapid PCR/HPIEX technique, we have identified amplification and deletion of the FGF-2 gene and the FGF-3, FGF-4 and c-erb-B2 oncogenes in human tumours of the breast, ovary and endometrium. Comparison of the data with tumour pathology has revealed possible associations between aberrant gene copy number and tumour type, invasiveness and metastases.

The multi-site tumour transplantation model for human endometrial carcinoma: a statistical evaluation.

We studied the effect of multi-site tumour transplantation on tumour growth by implanting varying numbers of EnCa 101 human endometrial tumours in athymic mice. One treatment group received a single tumour per mouse, another group received two tumours per mouse and a third group received four tumours per mouse. Tumour growth was sustained in all animals by implantation of oestradiol-17 beta pellets. We observed positive correlation between tumours within the same mouse, which implies that individual tumours are not statistically independent. The correlation is sufficiently large that failure to account for it in statistical design and analysis could result in studies with insufficient power and in spurious assertions of significance. Regression modelling of tumour growth curves showed that mean tumour volume per animal is not affected by the number of tumours growing on the animal; that is, the data are consistent with the null hypothesis that mean tumour volume is the same regardless of the number of tumours present. Our results therefore suggest that the use of multiple tumours per animal can increase the precision of experiments without loss of validity and at relatively little cost. However, correct and efficient analysis of the data so obtained requires more sophisticated techniques than those--such as fixed-effects analysis of variance and the two sample t-test--that assume independence of tumours.

Apparent resistance in human endometrial carcinoma during combination treatment with tamoxifen and progestin may result from desensitization following downregulation of tumor progesterone receptor

Combined treatment with tamoxifen and progestin effectively controlled human endometrial tumor growth in the nude mouse model. However, after an initial response the tumors became ‘resistant’ to continuous progestin administration. Tumors excised during the growth arrest or regrowth phases, showed return of the typical growth characteristics of EnCa-101, upon serial transplantation. The characteristic progesterone receptor proteins were observed by Western blot analysis in tamoxifen treated tumors, while tumors treated with both tamoxifen and progestin were devoid of receptor, beginning at 7 days after initiation of progestin therapy. Thus, downregulation of endometrial tumor PR resulting from continuous progestin administration presumably leads to desensitization to progestin, after an initial growth inhibitory response.

Sensitivity and insensitivity of breast cancer to tamoxifen

Tamoxifen is the endocrine treatment of choice for breast cancer. In several laboratory models in vivo tamoxifen is a tumoristatic agent. When MCF-7 breast cancer cells are inoculated into athymic mice, palpable tumors do not grow unless the animals are treated with estrogen, and tamoxifen inhibits estrogen-stimulated growth. If tamoxifen is stopped, tumors regrow. These results suggest that adjuvant tamoxifen therapy should involve long treatment periods (even lifetime) to prevent tumor recurrence. Unfortunately resistance to therapy and patient relapse inevitably occur, and such disease recurrence involving tamoxifen resistance is difficult to treat successfully. A laboratory model of endocrine therapy failure has been developed. When athymic mice with MCF-7 tumors are treated for 6–8 months with tamoxifen, several tumors grew and continued to grow in tamoxifen-treated mice. These estrogen receptor-positive tumors grow with either tamoxifen or estradiol. Tamoxifen-stimulated tumor growth has been observed in human endometrial tumors implanted into athymic animals. Growth of these tamoxifen-stimulated tumors can be inhibited with the pure antiestrogen ICI 164,384 upon withdrawal of tamoxifen. These data are discussed in terms of treatment strategies for tamoxifen-failed patients.

Influence of column length and pore size on high-performance ion-exchange chromatography of estrogen and progestin receptors

A high-performance liquid chromatographic (HPLC) procedure has been evaluated to establish a routine test in the clinical laboratory for measuring the profiles of estrogen and progestin receptor isoforms in human breast and endometrial tumors. This procedure will be used to determine if there is a relationship between particular isoform profiles and response to various endocrine therapies. Evaluation of various HPLC modes has shown that high-performance ion-exchange chromatography (HPIEC) with silica-based anion exchangers offers a promising approach. In this paper, we have compared HPIEC columns of different lengths (10 and 25 cm) and pore sizes (300, 500 and 1000 Å) in order to obtain an optimal separation procedure. Because of receptor lability, all investigations were performed at 4°C. The mobile phase consisted of 10-500 m M phosphate buffer, supplemented with the stabilizing agent, sodium molybdate at pH 7.4. Recoveries from each of the columns were between 70–100%. The length of the column did not influence significantly the retention time and salt concentration required for elution of receptor proteins. However, pore sizes appeared to alter these parameters. With a larger pore size (1000 Å), the retention of proteins was lower (elution with 50 m M phosphate) than that observed with the 500-Å pore size column (elution with 100 m M phosphate) or of the 300-Å pore size column (elution with 150 m M phosphate). Based solely on recovery patterns and peak shape, we conclude that separation of receptor isoforms on a 1000-Å, 25-cm column is best suited for clinical analysis.

In vitro growth characteristics and chemosensitivities of endometrial cancer using a soft agar clonogenic assay

A soft agar clonogenic assay was used to analyze 91 fresh human endometrial tumor samples for in vitro growth and chemosensitivities. Overall cloning success was 81%. Of the 75 samples adequate for drug testing (30 or more colonies per plate), histologic analysis demonstrated 36 adenocarcinomas, seven adenoacanthomas, ten adenosquamous carcinomas, nine mixed mesodermal sarcomas, seven carcinosarcomas, three papillary adenocarcinomas, and three clear-cell carcinomas. Mixed mesodermal sarcoma specimens demonstrated the most efficient growth, followed by the adenosquamous adenocarcinoma and adenoacanthoma samples. In vitro chemosensitivities were determined by colony inhibition resulting from continuous exposure of tumor cells to known achievable peak plasma and one-tenth peak plasma concentrations of a particular agent. The plating efficiency reflected the clinical virulence by cell type. Thus, we found that malignant endometrial tumors can be cloned in vitro, and the observed chemosensitivities reflect the relative clinical resistance of the tumors to these agents. Based on the high cloning success, this tumor type may be well suited as a model using in vitro soft agar cloning for new drug screening, evaluation of novel drug combinations, and studies of human tumor biology.

Heterotransplantation of human endometrial tumours to nude mice

Heterotransplantation of human endometrial tumours to nude mice

Effectiveness of steroid and imidazole drugs in inhibiting aromatase activity

Tamoxifen is the endocrine treatment of choice for breast cancer. In several laboratory models in vivo tamoxifen is a tumoristatic agent. When MCF-7 breast cancer cells are inoculated into athymic mice, palpable tumors do not grow unless the animals are treated with estrogen, and tamoxifen inhibits estrogen-stimulated growth. If tamoxifen is stopped, tumors regrow. These results suggest that adjuvant tamoxifen therapy should involve long treatment periods (even lifetime) to prevent tumor recurrence. Unfortunately resistance to therapy and patient relapse inevitably occur, and such disease recurrence involving tamoxifen resistance is difficult to treat successfully. A laboratory model of endocrine therapy failure has been developed. When athymic mice with MCF-7 tumors are treated for 6–8 months with tamoxifen, several tumors grew and continued to grow in tamoxifen-treated mice. These estrogen receptor-positive tumors grow with either tamoxifen or estradiol. Tamoxifen-stimulated tumor growth has been observed in human endometrial tumors implanted into athymic animals. Growth of these tamoxifen-stimulated tumors can be inhibited with the pure antiestrogen ICI 164,384 upon withdrawal of tamoxifen. These data are discussed in terms of treatment strategies for tamoxifen-failed patients.

Characterization of guinea pig anti-progestin receptor antiserum.

Antibody against the progestin receptor was raised in a guinea pig utilizing a partially purified receptor preparation from rabbit uterus. The antibody recognizes the cytosol and nuclear progestin receptor but not glucocorticoid, androgen, or estrogen receptors. In addition, the antibody recognizes the progestin receptor in normal human endometrium as well as that in human breast and endometrial tumor cytosols. Antigen: antibody complex formation between receptor and preimmune or immune serum was judged by shift in sedimentation coefficient on high-salt sucrose gradients, by exclusion from DEAE Affi-Gel Blue columns, and by adsorption with Protein A.

Human gynecologic cancers heterotransplanted into athymic nude rats

The serial transplants of human ovarian and endometrial tumors in nude mice were transplanted into nude rats. The transplants consisted of three lines of yolk sac tumors, designated as YST-1, YST-2, and YST-3 and two lines of endometrial adenocarcinoma, AD-30 and AD-35. The transplanted tumors grew much larger in nude rats than in nude mice, reaching more than 150 g in weight. The overall grafting success rate of these tumors was about 70% in nude rats whereas it had been almost 100% in nude mice. The histology of the transplanted tumor in nude rats was similar to that of the same tumor in nude mice. YST-1, YST-2, and YST-3 tumors produced the marker α-fetoprotein (AFP). Thus the transplanted tumors in nude rats seemed to preserve the characteristics of the original tumors. The usefulness of the nude rat as a tool for studying the efficacy of treatments on human malignant tumors is discussed.