NGFR and melanoma: To determine whether this NGFR-p53 feedback regulation might play a role in MIC renewal and proliferation, we first isolated MIC cells from two human melanoma SK-MEL-147 and SK-MEL-103 cell lines, which harbor wild-type (wt) p53 by selecting aldehyde dehydrogenase (ALDH)-positive spheroid-enriched melanoma cells as described in the “Materials and Methods”25,26 (Fig. 1a).