AR vaccine(Madison Vaccines, Inc.)

Androgen deprivation therapy (ADT) is the primary treatment for recurrent and metastatic prostate cancer. In addition to direct antitumor effects, ADT has immunomodulatory effects such as promoting T-cell infiltration and enhancing antigen processing/presentation. Previous studies in our laboratory have demonstrated that ADT also leads to increased expression of the androgen receptor (AR) and increased recognition of prostate tumor cells by AR-specific CD8+T cells. We have also demonstrated that ADT combined with a DNA vaccine encoding the AR significantly slowed tumor growth and improved the survival of prostate tumor-bearing mice. The current study aimed to investigate the impact of the timing and sequencing of ADT with vaccination on the tumor immune microenvironment in murine prostate cancer models to further increase the antitumor efficacy of vaccines.

Male FVB mice implanted with Myc-CaP tumor cells, or male C57BL/6 mice implanted with TRAMP-C1 prostate tumor cells, were treated with a DNA vaccine encoding AR (pTVG-AR) and ADT. The sequence of administration was evaluated for its effect on tumor growth, and tumor-infiltrating immune populations were characterized.

Vaccination prior to ADT (pTVG-AR → ADT) significantly enhanced antitumor responses and survival. This was associated with increased tumor infiltration by CD4+ and CD8+ T cells, including AR-specific CD8+T cells. Depletion of CD8+T cells prior to ADT significantly worsened overall survival. Following ADT treatment, however, Gr1+ myeloid-derived suppressor cells (MDSCs) increased, and this was associated with fewer infiltrating T cells and reduced tumor growth. Inhibiting Gr1+MDSCs recruitment, either by using a CXCR2 antagonist or by cycling androgen deprivation with testosterone replacement, improved antitumor responses and overall survival.

Vaccination prior to ADT significantly improved antitumor responses, mediated in part by increased infiltration of CD8+T cells following ADT. Targeting MDSC recruitment following ADT further enhanced antitumor responses. These findings suggest logical directions for future clinical trials to improve the efficacy of prostate cancer vaccines.

This study aimed to clarify potential candidates for anatomic resection (AR) among patients with pathological T1-T2 (pT1-T2) hepatocellular carcinoma (HCC) and to determine whether AR is effective for HCC with microscopic vascular invasion (MVI).

We retrospectively analyzed 288 patients with pT1a (n = 50), pT1b (n = 134) or pT2 (n = 104) HCC who underwent curative-intent resection between 1990 and 2010. Surgical outcomes were compared between patients who underwent AR (n = 189) and those who underwent nonanatomic resection (NAR; n = 99) according to pT category and MVI status.

Patients who underwent AR were more likely to have good hepatic functional reserve and an aggressive primary tumor than those who underwent NAR. When patients were stratified according to pT category, AR had a more favorable impact on survival than NAR only in patients with pT2 HCC in univariate (5-year survival, 51.5% vs. 34.6%; p = 0.010) and multivariate analysis (hazard ratio 0.505; p = 0.014). However, AR had no impact on survival in patients with pT1a or pT1b HCC. In patients with MVI (n = 57), AR achieved better survival than NAR (5-year survival, 52.0% vs. 16.7%; p = 0.019) and was an independent prognostic factor (hazard ratio 0.335; p = 0.020). In patients without MVI (n = 231), there was no significant difference in survival between the two groups (p = 0.221).

AR was identified as an independent factor in improved survival in patients with pT2 HCC or HCC with MVI.