Background: Androgen signaling plays a critical role in the development of prostate cancer and its progression. However, androgen-independent prostate cancer cells emerge after hormone ablation therapy, resulting in significant clinical problems. We have previously demonstrated that the HOXB13 homeodomain protein functions as a prostate cancer cell growth suppressor by inhibiting androgen-mediated signals. However, the role of the HOXB13 in androgen-independent growth of prostate cancer cells remains unexplained. Results: In this report, we first demonstrated that HOXB13 was highly overexpressed in hormone-refractory tumors compared to tumors without prostate-specific antigen after initial treatment. Functionally, in an androgen-free environment minimal induction of HOXB13 in LNCaP prostate cancer cells, to the level of the normal prostate, markedly promoted cell proliferation while suppression inhibited cell proliferation. The HOXB13-mediated cell growth promotion in the absence of androgen, appears to be mainly accomplished through the activation of RB-E2F signaling by inhibiting the expression of the p21^waf tumor suppressor. Indeed, forced expression of HOXB13 dramatically decreased expression of p21^waf; this inhibition largely affected HOXB13-mediated promotion of E2F signaling. Conclusions: Taken together, the results of this study demonstrated the presence of a novel pathway that helps understand androgen-independent survival of prostate cancer cells. These findings suggest that upregulation of HOXB13 is associated with an additive growth advantage of prostate cancer cells in the absence of or low androgen concentrations, by the regulation of p21-mediated E2F signaling.

Cho YH, et al. Korean J Urol. 2014 Jul;55(7):453-459. https://doi.org/10.4111/kju.2014.55.7.453

Only 54% of prostate cancer cases in Korea are localized compared with 82% of cases in the US. Furthermore, half of Korean patients are upgraded after radical prostatectomy (41.6%-50.6%). We investigated the risk factors for upgrading and/or upstaging of low-risk prostate cancer after radical prostatectomy. We retrospectively reviewed the medical records of 1159 patients who underwent radical prostatectomy at five hospitals in Honam Province. Preoperative data on standard clinicopathological parameters were collected. The radical prostatectomy specimens were graded and staged and we defined a "worsening prognosis" as a Gleason score ≥ 7 or upstaging to ≥ pT3. Multivariate logistic regression models were used to assess factors associated with postoperative pathological upstaging. Among the 1159 patients, 324 were classified into the clinically low-risk group, and 154 (47.5%) patients were either upgraded or upstaged. The multivariable analysis revealed that the preoperative serum prostate-specific antigen level (odds ratio [OR], 1.131; 95% confidence interval [CI], 1.007-1.271; P= 0.037), percent positive biopsy core (OR: 1.018; 95% CI: 1.002-1.035; P= 0.032), and small prostate volume (≤30 ml) (OR: 2.280; 95% CI: 1.351-3.848; P= 0.002) were predictive of a worsening prognosis. Overall, 47.5% of patients with low-risk disease were upstaged postoperatively. The current risk stratification criteria may be too relaxed for our study cohort.

The survival benefits of adrenalectomy (ADx) in the setting of metastatic cancer and prognostic factors for recurrence-free (RFS) and overall survival (OS) after adrenalectomy for metastatic carcinoma are still under debate. We evaluated the impact of clinicopathological variables on RFS and OS after ADx for metastatic carcinoma in patients with primary cancer.

Chung JW, et al. Investig Clin Urol. 2021 Sep;62(5):545-552. https://doi.org/10.4111/icu.20210105

Key words: Prostatic Neoplasms; Prostate-Specific Antigen; Diagnosis