HOXB7 and melanoma: The homeodomain transcription factor HOXB7, a member of the Hox family, is closely involved in the development of cancer, and it has been reported to be aberrantly expressed in a variety of cancers, including melanoma [9], breast cancer [10–15], gastric cancer [16, 17], liver cancer [18, 19], colorectal cancer [20], and esophageal cancer [21].