Biomarkers for the Management of Castration-Resistant Prostate Cancer: We Are Not There Yet

Baseline basophil and basophil-to-lymphocyte status is associated with clinical outcomes in metastatic hormone sensitive prostate cancer

BACKGROUND

Biomarkers have the potential to provide clinical guidance, but there is limited data for biomarkers in metastatic hormone sensitive prostate cancer (mHSPC).

METHODS

We performed a retrospective multicenter review from Winship Cancer Institute at Emory University and Georgia Cancer Center for Excellence at Grady Memorial Hospital (2014-2020) in the United States of America (USA). We collected demographics, disease characteristics, and laboratory data, including complete blood counts (CBC) at the start of upfront therapy. We evaluated overall survival (OS) and progression-free survival (PFS) associated with baseline lab values.

RESULTS

165 patients were included with a median follow-up time of 33.5 months (mo). 105 (63.6%) had Gleason scores of 8-10 and 108 (65.9%) were classified as high-volume disease. 92 patients received upfront docetaxel (55.8%) and 73 received upfront abiraterone (44.2%). Univariate analyses (UVA) and multivariable analyses (MVA) identified worse clinical outcomes (CO) associated with elevated basophils and basophil-to-lymphocyte ratio (BLR). Based on MVA, elevated basophils (defined as ≥0.1, optimal cut) were associated with a hazard ratio (HR) of 3.51 (95% CI 1.65-7.43, P 0.001) for OS and HR of 1.88 (95% CI 1.05-3.38, P 0.034) for PFS. Our MVA also found that BLR ≥0.0142 was associated with HR 2.11 (95% CI 1.09-4.10, P 0.028) for OS; however, PFS was not statistically significant.

CONCLUSION

We conclude that elevated baseline basophils and BLR are associated with worse clinical outcomes in mHSPC. Although results require further validation, BLR is a potential prognostic biomarker.

Annexin A1 promotes the nuclear localization of the epidermal growth factor receptor in castration-resistant prostate cancer

Epidermal growth factor receptor is a cancer driver whose nuclear localization has been associated with the progression of prostate cancer to the castration-resistant phenotype. Previous reports indicated a functional interaction between this receptor and the protein Annexin A1, which has also been associated with aggressive tumors. The molecular pathogenesis of castration-resistant prostate cancer remains largely unresolved, and herein we have demonstrated the correlation between the expression levels and localization of the epidermal growth factor receptor and Annexin A1 in prostate cancer samples and cell lines. Interestingly, a higher expression of both proteins was detected in castration-resistant prostate cancer cell lines and the strongest correlation was seen at the nuclear level. We verified that Annexin A1 interacts with the epidermal growth factor receptor, and by using prostate cancer cell lines knocked down for Annexin A1, we succeeded in demonstrating that Annexin A1 promotes the nuclear localization of epidermal growth factor receptor. Finally, we showed that Annexin A1 activates an autocrine signaling in castration-resistant prostate cells through the formyl peptide receptor 1. The inhibition of such signaling by Cyclosporin H inhibits the nuclear localization of epidermal growth factor receptor and its downstream signaling. The present work sheds light on the functional interaction between nuclear epidermal growth factor receptor and nuclear Annexin A1 in castration-resistant prostate cancer. Therefore, strategies to inhibit the nuclear localization of epidermal growth factor receptor through the suppression of the Annexin A1 autocrine loop could represent an important intervention strategy for castration-resistant prostate cancer.

Neuron-specific enolase has potential value as a biomarker for [18F]FDG/[68Ga]Ga-PSMA-11 PET mismatch findings in advanced mCRPC patients

BACKGROUND

PSMA-targeted radioligand therapy (PSMA-RLT) yielded impressive results in the metastasized castration-resistant prostate carcinoma (mCRPC) setting. High expression of PSMA is essential for successful PSMA-RLT. However, some patients develop [18F]FDG-avid lesions with low or no PSMA expression ([18F]FDG/[68Ga]Ga-PSMA-11 mismatch findings on PET/CT) in the course of treatment. Those lesions are not affected by PSMA-RLT and a change in therapy management is needed. To enable early mismatch detection, possible blood parameters as indicators for the occurrence of [18F]FDG/[68Ga]Ga-PSMA-11 mismatch findings on PET/CT were evaluated.

METHODS

Retrospective study of N = 66 advanced mCRPC patients with dual [68Ga]Ga-PSMA-11 and [18F]FDG PET/CT imaging within 4 weeks, who were referred for or received [177Lu]Lu-PSMA-617 radioligand therapy. Prostate-specific antigen (PSA), neuron-specific enolase (NSE), gamma-glutamyltransferase (GGT), and alkaline phosphatase (ALP) were tested as indicators for the occurrence of [18F]FDG/[68Ga]Ga-PSMA-11 mismatch findings. Additional to absolute values, relative changes (ΔPSA, ΔNSE, ΔGGT, ΔALP) over a period of 4 ± 1 weeks prior to [18F]FDG PET/CT were analyzed.

RESULTS

In total, 41/66 (62%) patients revealed at least one [18F]FDG/[68Ga]Ga-PSMA-11 mismatch finding on PET/CT. These mismatch findings were detected in 13/41 (32%) patients by screening for and in 28/41 (68%) patients during PSMA-RLT. NSE serum level (55.4 ± 44.6 μg/l vs. 18.5 ± 8 μg/l, p < 0.001) and ΔNSE (93.8 ± 124.5% vs. 2.9 ± 39.5%, p < 0.001) were significantly higher in the mismatch group than in the non-mismatch group. No significant differences were found for serum PSA (p = 0.424), ΔPSA (p = 0.417), serum ALP (p = 0.937), ΔALP (p = 0.611), serum GGT (p = 0.773), and ΔGGT (p = 0.971). For NSE and ΔNSE, the maximum value of the Youden index in ROC analysis was at a cut-off level of 26.8 μg/l (sensitivity 78%, specificity 96%) and at + 13.9% (sensitivity 84%, specificity 75%), respectively. An introduced scoring system of both parameters achieved a sensitivity of 90% and a specificity of 88% for the occurrence of [18F]FDG/[68Ga]Ga-PSMA-11 mismatch.

CONCLUSION

We observed a significantly higher absolute serum concentration and a higher relative increase of NSE in advanced mCRPC patients with [18F]FDG-avid and insufficient PSMA expressing metastases ([18F]FDG/[68Ga]Ga-PSMA-11 mismatch findings on PET/CT) in our cohort. NSE might be used as a potential laboratory indicator for [18F]FDG/[68Ga]Ga-PSMA-11 mismatch findings, if this observation is confirmed in future, ideally prospective, studies in larger patient cohorts.

Association of Hyponatremia With Survival in Patients With Castration-resistant Prostate Cancer: A Clinical Commentary

INTRODUCTION

The aim of this study was to evaluate the prognostic value of hyponatremia in patients with castration-resistant prostate cancer (CRPC) undergoing docetaxel chemotherapy.

PATIENTS AND METHODS

We retrospectively assessed 186 patients who received docetaxel chemotherapy in addition to androgen deprivation for CRPC between 2005 and 2015. We stratified the patients according to their pre-chemotherapy serum sodium level. Hyponatremia was defined as sodium < 135 mmol/L. A Cox proportional regression model was used to estimate overall survival (OS).

RESULTS

The median sodium level was 139 mmol/L (interquartile range, 137-141 mmol/L). Hyponatremia was detected in 13 (6.9%) patients. One-half of the patients died during the studied period. The presence of hyponatremia was associated with a decreased probability of OS (hazard ratio, 2.5; 95% confidence interval, 1.0-6.3; P = .04) in univariate analysis. These findings could not be confirmed in the multivariable OS model (P = .21).

CONCLUSION

We observed an association between hyponatremia and worse survival outcomes in our patients with CRPC undergoing docetaxel chemotherapy. However, further well-designed studies with full workup of hyponatremia are needed to validate these findings and to identify the underlying causes for this association in patients with CRPC.

Alkaline phosphatase in metastatic castration-resistant prostate cancer: reassessment of an older biomarker

Since most patients with metastatic castration-resistant prostate cancer (mCRPC) have bone metastases, it is important to understand the potential impact of therapies on prognostic biomarkers, such as ALP. Clinical studies involving mCRPC life-prolonging agents (i.e., sipuleucel-T, abiraterone, enzalutamide, docetaxel, cabazitaxel, and radium-223) have shown that baseline ALP level is prognostic for overall survival, and may be a better prognostic marker for overall survival than prostate-specific antigen in patients with bone-dominant mCRPC. Mechanism of action differences between therapies may partly explain ALP dynamics during treatment. ALP changes can be interpreted within the context of other parameters while monitoring disease activity to better understand the underlying pathology. This review evaluates the current role of ALP in mCRPC.