Oncogenes: a review with relevance to cancers of the urogenital tract

Histochemical examination of expression of ras p21 protein and R 1881-binding protein in human prostatic cancers

Expression of ras p21 was examined with monoclonal antibody RASK-3 in normal, benign hyperplasic, and cancerous prostates. In patients with stage D2 disease who received endocrine therapy, the relation between ras p21 expression, response to therapy, and prognosis was studied. In these patients, R 1881-binding protein (androgen receptor and progestin-binding protein) was also examined. Non-cancerous cells and most cancer cells from stage A patients did not express ras p21, while expression increased with both higher staging and grading. Staging pelvic lymphadenectomy was done in some stage A2-C cases, and presence of nodal metastasis was correlated with ras p21 expressions in the primary tumours. In stage D2, there was no correlation between ras p21 expression and R 1881-binding protein. Response to therapy and survival did not correlate with expression of ras p21, but was influenced by presence of R 1881-binding protein.

Oncogene expression in prostate cancer: Dunning R3327 rat dorsal prostatic adenocarcinoma system

Steady-state levels of myc, fos, p53, sis, and neu mRNAs were measured in eight variants derived from the Dunning R3327 rat prostate adenocarcinoma and compared to levels in normal dorsal prostate. Expression of the myb and erbB oncogenes in the Dunning tumors was below the limits of detection. Myc, p53, and sis mRNA levels in all tumors were at or above control levels. Fos mRNA levels were below control levels in four of five anaplastic tumors and were above control levels in the remaining tumors. A comparison of mRNA levels along the two Dunning lineages revealed that increased expression of these oncogenes did not correlate with tumor progression.

The partial dependency of human prostatic growth factor on steroid hormones in stimulating thymidine incorporation into DNA

Growth factors stimulating DNA synthesis in mouse 3T3, human DU145, and LNCaP were partially purified from human benign hyperplastic and cancerous prostates. These factors have a high affinity for heparin sepharose and are eluted from the heparin-sepharose column, at 1.2 to 1.9 M NaCl. In normal prostates, the high affinity human prostatic growth factor occurred only in extremely small amounts. The high affinity growth factors stimulate DNA synthesis in 3T3, DU145, and LNCaP. Stimulation was significantly enhanced by 5 alpha-dihydrotestosterone and 17 beta-estradiol in the androgen sensitive LNCaP cell line. SDS-PAGE and isoelectrofocusing confirmed that the partially purified factors had a molecular weight of 18 kDa and acidic isoelectric points of pH 3.6 and 4.7.

Activated Ki-ras oncogene in human prostatic adenocarcinoma

The role of cellular oncogenes in the development of human prostate cancer has not been extensively studied. A search for activated oncogenes was undertaken by testing DNA isolated from prostatic adenocarcinoma tissues for transforming activity in a 3T3 transfection assay. A transforming sequence homologous to Ki-ras was detected in one of the samples. DNA from the other cancers was negative in the transformation assay, suggesting that the activation of oncogenes, at least those detectable by the 3T3 transfection assay, is not a frequent event in prostate cancer. Amplification of genomic oncogene sequences in prostatic tissues was also examined, but amplification of Ki-ras, Ha-ras, c-myc, N-myc, c-sis, or c-fos was not detectable in any of the samples.