A Putatively Functional Haplotype in the Gene Encoding Transforming Growth Factor Beta-1 as a Potential Biomarker for Radiosensitivity

Purpose To determine whether genetic variability in TGFB1 is related to circulating transforming growth factor-β1 (TGF-β1) plasma concentrations after radiotherapy and to radiosensitivity of lymphoid cells. Patients and Methods Transforming growth factor-β1 plasma concentrations ( n = 79) were measured in patients 1 year after radiotherapy and chromosomal aberrations ( n = 71) ex vivo before therapy start. Furthermore, TGF-β1 secretion and apoptosis were measured in isolated peripheral blood mononuclear cells of 55 healthy volunteers. These phenotypes were analyzed in relation to five germline polymorphisms in the 5′ region of the TGFB1 gene. Because of high linkage disequilibrium, these fi…