KRT19 and thymoma: When cFLIP RNA levels were normalized for cytokeratin 19 (CK19) expression levels (as surrogate marker of epithelial cell content), the difference between thymomas and TSCCs disappeared, while the individual cFLIP/CK19 ratios of the different thymic tumor subtypes (mean ratios 1,58 - 2,0) were still significantly higher than the ratio of NTs (ratio 0,33 +/-0,13) (Supplementary Figure 2 and Table 1).