The Inconvenience of Convenience Cohorts: Rhabdomyosarcoma and the PAX-FOXO1 Biomarker

Convenience cohorts comprise individuals thought to represent the general population, but chosen because they are readily available for evaluation, rather than at random. As such, these methods are subject to bias and may be misleading. Convenience cohorts have been used to investigate the prognostic significance of chromosomal translocations between the PAX3 or PAX7 and the FOXO1 genes in rhabdomyosarcoma, the most common pediatric sarcoma. However, retrospective studies assessing the role of PAX-FOXO1 translocations have yielded inconsistent results. This review highlights the findings from several clinical correlation studies of the PAX-FOXO1 biomarker and illustrates the challenges of using such methods to draw clinical conclusions. Cancer Epidemiol Biomarkers Prev; 21(7); 1012-8. (C)2012 AACR.