Molecular markers and Schistosoma-associated bladder carcinoma: A systematic review and meta-analysis

Molecular mechanisms and pathogenesis of schistosomal-associated bladder cancer (SABC), one of the most common malignancies in Africa and parts of the Middle East, is still unclear. Identification of host molecular markers involved in schistosomal related bladder carcinogenesis is of value in prediction of high-risk group, early detection and timely intervention.

PubMed, Scopus, Google Scholar, Cochrane Library and African Journals Online databases were systematically searched and reviewed. A total of 63 articles reporting 41 host molecular factors were included in the meta-analysis.

Pooled odds ratio demonstrated associations of p53 expression, telomerase activity and sFas with SABC as compared to other schistosomal patients (p53 expression: OR=9.46, 95%CI=1.14-78.55, p=0.04; telomerase by TERT: OR=37.38, 95%CI=4.17-334.85, p=0.001; telomerase by TRAP: OR=10.36, 95%CI=6.08-17.64, p<0.00001; sFas: OR=34.37, 95%CI=3.32-355.51, p=0.003). In comparison to bladder cancers of other etiology, positive associations were found between SABC and p15 deletion, p16 deletion, telomerase activity and sFas (p15 deletion: OR=4.20, 95%CI=2.58-6.82, p<0.00001; p16 deletion: OR=4.93, 95%CI=2.52-9.65, p<0.00001; telomerase by TERT: OR=3.01, 95%CI=1.51-5.97, p=0.002; telomerase by TRAP: OR=2.66, 95%CI=1.18-6.01, p=0.02; sFas: OR=4.50, 95%CI=1.78-11.40, p=0.001). Other identified associations were reported by few numbers of studies to enable reliable interpretation.

Variations in gene expression or genomic alterations of some molecular markers in SABC as compared to non-SABC or other schistosomal patients were identified. These suggest minute differences in the pathogenesis and physiological profile of SABC, in relation to non-SABC.