As the qRT-PCR analysis performed on Mel888 and A375M cell lines, as representative primary and metastatic melanomas, did not show any significant modulation of both mRNAs in response to HXR9 (Fig. 5d), we hypothesized a post-transcriptional regulation of HOXB7 as well as PBX2. The gene discussed is PBX2; the disease is melanoma.