(A) In primary melanoma, where methylation represses miR-155-5p expression and KPC1 is highly expressed, excess p50–p50 homodimers suppress tumor-promoting p65–p50 heterodimers or modify transcription of NF-κB-target genes with other transcriptional modulators, resulting in suppressive effect on melanoma cell proliferation. (B) Contrarily, metastatic melanoma, which has low DNA methylation / high miR-155-5p and low KPC1 expression, lacks excess p50–p50 homodimers, promoting cell proliferation.