Expression of TCF12, OSBPL1A and TRAK1 isoforms in colorectal neoplasia. A, Exon structure and exon array expression of TCF12 in normal mucosa (n = 24) and tumor (n = 84) samples. Error bars represent SE. B, Exon array expression levels of the alternative start exon (1B) in mucosa samples, adenomas, and carcinomas (MSS and MSI). C, qRT-PCR validation of exon 1B expression, primer position is indicated in A. D, Exon structure and exon array expression of OSBPL1A as in A. E, Exon array isoform ratio of OSBPL1A as in B. F, qRT-PCR validation of OSBPL1A isoform ratio. G, Exon structure and exon array expression of TRAK1 as in A. H, Exon array isoform ratio of TRAK1 as in B. I, qRT-PCR validation of TRAK1 isoform ratio. * = p < 0.05, ** = p < 0.01 and *** = p < 0.001.