Prostate endocrine tumors

Patients must be monitored to assess their response to treatment and to detect recurrent diseases. PSA as a specific marker for prostate cancer is most useful in monitoring patients who have been treated with radical prostatectomy, radiation therapy, or endocrine therapy. The concentration of PSA falls to undetectable levels following a radical prostatectomy because all prostate tissue has been removed. Generally, PSA is measured at periodic intervals. In studies, the extent of disease at the time of surgery correlated well with the postoperative PSA concentration. A significant measurable PSA concentration after prostatectomy indicates that residual tumor may be present. PSA concentrations decline gradually after radiation therapy (36). 

Embryonic exposure to vinclozolin, an antiandrogenic endocrine disruptor, has been shown to promote prostate disease, kidney disease, immune system abnormalities, testicular abnormalities, breast and other tumor development, and a number of blood abnormalities in the F1-F4 generations of laboratory animals. I8,91 The effects observed were noted in the adults of the four ensuing generations that followed the exposure. 

For the overwhelming majority of cancers, the administration of thymosin (either TF5 or Toj) or other thymic factors alone does not result in tumor regression (reviewed in Schulof and Goldstein, 1983 Dillman et al., 1982). However, the administration of TF5 has caused regression in approximately 10 to 20% of patients with renal cancer and some with prostate cancer (Wara et al., 1984 Schulof et al., 1984). Since many of these patients exhibited normal pretreatment immune profiles and since each of these cancers is considered to be a hormonally responsive tumor, it has been suggested that thymosin may act by an undefined endocrine mechanism in these disorders. 

Over expression of tumor suppressor gene bcI-2 plays an important role in cellular resistance to apoptosis caused by various factors (77). Lin et al have shown that over expression of anti-apoptotic Bcl-2 and Bc1-Xl proteins may play a role in the development of resistance to cancer therapy 18). Functional over expression of Bcl-2 has been reported to confer an anti-apoptotic potential in a variety of cell types. The role of Bcl-2 in epithelial cell-cycle control and in interactions with other cell-cycle regulators is not clearly understood. Its expression has been correlated with the hormone- and chemo-resistant phenotype in advanced prostate cancer 19). Granville et al have shown that overexpression of Bcl-2 in HL-60 cells prevented apoptosis-related events including caspase 3 and 6 activation, poly (ADP-ribose) polymerase cleavage by photodynamic therapy (20). Over expression of HER2 in estrogen receptor (ER)-positive human breast tumors has been associated with resistance to endocrine therapy. 

Ohshima M, Ward JM, Wenk ML (1985) Preventive and enhancing effects of retinoids on the development of naturally occurring tumors of skin, prostate gland, and endocrine pancreas in aged male aci/seghapbr rats. J Nat Cancer Inst 74 517-524... 

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