B2M and renal carcinoma: Martayan et al. [47] specifically questioned the differences in the folding and conformational orientations between B2m-associated (B2m transfectant cells) and B2m-free HLA HCs (B2m-deficient cells) in a kidney carcinoma cell line (KJ29 cells) that is positive for HLA-A2, -B27, and –Cw1 and does express low but significant amounts of free HLA-Cw1 HCs at the cell surface in B2m-deficient cells.