A Calcium-Centered Socio-Ecological Model of Prostate Cancer Disparities: Preliminary Studies and Findings

Abstract

Western studies have established that men from African descent are disproportionally affected by prostate cancer (PCa). Annual incidence rates in this population vary from 1.5 to 2 times when compared to their counterparts from other racial groups. They also record the worse outcomes in terms of prognosis. Additionally, with the rise of PCa in Subsaharan Africa, new cancer control policies and programs are increasingly demanded. Understanding therefore, factors that underpin racial inequality in distribution and especially why the disease preferentially niches in African males can help better address PCa in both Western and Subsaharan countries. There is also the potential to develop new therapeutic options. A genetic susceptibility was first hypothesized, however available data suggest that they only account for less than 20% of the cases. Current findings from epidemiological and molecular investigations suggest an important role of complex and dynamic environmental interactions involving the different levels of calcium regulation. Using a multi-method design, this research aims at developing an integrative mechanistic model of PCa. We argue that given the versatile and ubiquitous role calcium plays in nutrition, physical environment, and in key cellular processes, that mineral cation is central to prostate tumorigenesis and in shaping its populational distribution. Thus a tree-level investigation was conducted: (i) a critical analysis and synthesis of empirical evidence on calcium interactions with cancer mechanisms (ii) a population-wide prospective cohort study of calcium intake patterns in a group of Subsaharan males in Côte d’Ivoire, namely the African Prostate Cancer Study (APCS) (iii) a proteomics research investigating the responses of prostate cancer cell lines when exposed to a high affinity synthetic calcium binding peptide. This monograph describes the research methods, instruments design and validation and the preliminary findings of the ongoing research, portions of which have already been published, presented at two international cancer seminars or under review. Findings at this stage include: mechanistic models of prostate cancer differential distribution and outcomes, a novel calcium questionnaire specific to African diet, synthesis of a high affinity calcium-binding peptide (Peptide#1). New concepts and constructs related to prostatic carcinogenesis have been developed as well.