Figure 4

Mean normalized expression estimates of MITF and its transcript variants in melanocyte (N) and melanoma (T) cell lines, and of TPM4 and its transcript variants in non-oncogenic and oncogenic breast cell lines (HMEC-N; MCF7-T) and tissues. (A) Notice that although the gene level expression of MITF was not significantly different between melanoma and melanocytes, three of its isoforms showed significant differences in their expression. Whereas ENST00000352241 was overexpressed, ENST00000433517 and ENST00000472437 were underexpressed in melanoma. (B) Similarly, two transcript variants of TPM4 showed opposing expression patterns between the non-oncogenic HMEC and the MCF7 breast-cancer cell lines. (C) Validation results via RT-qPCR experiments showing the relative fold expressions of the two major transcript variants of TMP4 (ENST00000300933 and ENST00000344824) in various human breast-cancer tissue subtypes compared with the surrounding matched non-oncogenic breast tissue. We analyzed two patient samples for estrogen receptor (ER)-positive breast-cancer tissues (ER+S1 and ER+S2) and one patient sample each for Her2 gene-positive breast cancer (Her2+) and triple-negative breast cancer (TNBC) subtypes. MCF7 is an ER+ breast-cancer cell line.