Reinforcing our observations regarding the relationship of LETM1 with cellular growth signaling, LETM1 silencing resulted in decreased protein levels of PDGFB and mRNA expression of PDGFB, PDGFBR and THBS4 in BCPAP cells (Figure 4D and 4E) and 8505C cells (human anaplastic thyroid cancer cell line, Figure 4F and 4G). This evidence concerns the gene THBS4 and thyroid gland undifferentiated (anaplastic) carcinoma.