How Prostate Cancer Cells Use Strategy Instead of Brute Force to Achieve Metastasis

Identification and validation of the prognostic impact of metastatic prostate cancer phenotypes

INTRODUCTION

Castration-sensitive metastatic prostate cancer is heterogeneous. Our objective is to identify metastatic prostate cancer phenotypes and their prognostic impact on survival.

MATERIALS AND METHODS

The National Cancer Database was queried. The Surveillance, Epidemiology, and End Results database was used for validation. Patterns were split into: nonregional lymph node, bone only, and visceral (any brain/liver/lung). Hazard ratios (HR) with 95% confidence intervals (CI) were calculated for the univariate and multivariate Cox proportional hazards regression models, odds ratios were calculated, Kaplan-Meier curves were generated, and a nomogram of the multivariate regression model was created.

RESULTS

The training set included 13,818 men; bone only was most common (n = 11,632, 84.2%), then nonregional lymph node (n = 1388, 10.0%), and any visceral (brain/liver/lung; n = 798, 5.8%). Risk of death was increased by metastases to a visceral organ versus nonregional lymph node (HR = 2.26; 95% CI [2.00, 2.56]), bone only metastases versus nonregional lymph node (HR = 1.57; 95% CI [1.43, 1.72]), T-stage 4 versus 1 (HR = 1.27; 95% CI [1.17, 1.36]), Grade Group 5 versus 1 (HR = 1.93; 95% CI [1.61, 2.31]), PSA > 20 ng/mL versus < 10 ng/mL (HR = 1.32; 95% CI [1.23, 1.42]), and age ≥ 80 versus < 50 (HR = 1.96; 95% CI [1.69, 2.29]). On internal validation, the model had C-indices 20.5%, 22.7%, and 14.6% higher than the current staging system for overall survival, 1-year, and 5-year survival, respectively.

CONCLUSION

We developed and validated prognostic metastatic prostate cancer phenotypes that can assist risk stratification to potentially personalize therapy. Our nomogram (https://tinyurl.com/prostate-met) may be used to predict survival.

Circulating erythroblast abnormality associated with systemic pathologies may indicate bone marrow damage

Background:

The circulating rare cell population is diverse and rich in diagnostic information. Its characterization and clinical exploitation by cell-based liquid biopsy is an ongoing research task. Bone marrow is one of the major contributors to the peripheral blood rare cell population and, consequently, determines individual rare cell profiles thus depending on bone marrow health status. Bone marrow damage has been associated with aggressive or late-stage systemic diseases and egress of various bone marrow cells into the blood circulation. The association of quantity and heterogeneity of circulating erythroblast with bone marrow damage is of particular interest.

Methods:

Circulating CD71^high/CD45-/Hoechst^high blast cells from healthy, noncancer- and cancer-afflicted donors were enriched by CD45 depletion and analyzed by immunofluorescence microscopy.

Results:

A new finding of aberrant and mitotic circulating erythroid-like cells that appear similar across blood donors afflicted with various systemic pathologies is reported. Further presented is a classification of said erythroblast-like cells in nine subcategories according to morphological differences between phenotypically similar cells.

Conclusion:

Aberrant and mitotic bone marrow-derived rare circulating erythroid-like cells can be detected in the blood of afflicted individuals but not in healthy donors, suggesting the cause of bone marrow damage.

Tumor Hypoxia and Circulating Tumor Cells

Circulating tumor cells (CTCs) are a rare tumor cell subpopulation induced and selected by the tumor microenvironment's extreme conditions. Under hypoxia and starvation, these aggressive and invasive cells are able to invade the lymphatic and circulatory systems. Escaping from the primary tumor, CTCs enter into the bloodstream to form metastatic deposits or re-establish themselves in cancer's primary site. Although radiotherapy is widely used to cure solid malignancies, it can promote metastasis. Radiation can disrupt the primary tumor vasculature, increasing the dissemination of CTCs. Radiation also induces epithelial-mesenchymal transition (EMT) and eliminates suppressive signaling, causing the proliferation of existent, but previously dormant, disseminated tumor cells (DTCs). In this review, we collect the results and evidence underlying the molecular mechanisms of CTCs and DTCs and the effects of radiation and hypoxia in developing these cells.

Oligometastatic Prostate Adenocarcinoma. Clinical-Pathologic Study of a Histologically Under-Recognized Prostate Cancer

The clinical parameters and the histological and immunohistochemical findings of a prospective protocolized series of 27 prostate carcinoma patients with oligometastatic disease followed homogeneously were analyzed. Lymph nodes (81.5%) and bones (18.5%) were the only metastatic sites. Local control after metastatic directed treatment was achieved in 22 (81.5%) patients. A total of 8 (29.6%) patients developed castration-resistant prostate cancer. Seventeen (63%) patients presented with non-organ confined disease. The Gleason index 8-10 was the most frequently observed (12 cases, 44.4%) combined grade. Positive immunostainings were detected with androgen receptor (100%), PGP 9.5 (74%), ERG (40.7%), chromogranin A (29.6%), and synaptophysin (18.5%) antibodies. The Ki-67 index value > 5% was observed in 15% of the cases. L1CAM immunostaining was negative in all cases. Fisher exact test showed that successful local control of metastases was associated to mild inflammation, organ confined disease, Ki-67 index < 5%, and Gleason index 3 + 3. A castration resistant status was associated with severe inflammation, atrophy, a Gleason index higher than 3 + 3, Ki-67 index ≥ 5%, and positive PGP 9.5, chromogranin A, and synaptophysin immunostainings. In conclusion, oligometastatic prostate adenocarcinoma does not have a specific clinical-pathologic profile. However, some histologic and immunohistochemical parameters of routine use may help with making therapeutic decisions.

The Role of Cancer-Associated Fibroblasts in Prostate Cancer Tumorigenesis

Tumors strongly depend on their surrounding tumor microenvironment (TME) for growth and progression, since stromal elements are required to generate the optimal conditions for cancer cell proliferation, invasion, and possibly metastasis. Prostate cancer (PCa), though easily curable during primary stages, represents a clinical challenge in advanced stages because of the acquisition of resistance to anti-cancer treatments, especially androgen-deprivation therapies (ADT), which possibly lead to uncurable metastases such as those affecting the bone. An increasing number of studies is giving evidence that prostate TME components, especially cancer-associated fibroblasts (CAFs), which are the most abundant cell type, play a causal role in PCa since the very early disease stages, influencing therapy resistance and metastatic progression. This is highlighted by the prognostic value of the analysis of stromal markers, which may predict disease recurrence and metastasis. However, further investigations on the molecular mechanisms of tumor-stroma interactions are still needed to develop novel therapeutic approaches targeting stromal components. In this review, we report the current knowledge of the characteristics and functions of the stroma in prostate tumorigenesis, including relevant discussion of normal prostate homeostasis, chronic inflammatory conditions, pre-neoplastic lesions, and primary and metastatic tumors. Specifically, we focus on the role of CAFs, to point out their prognostic and therapeutic potential in PCa.