Cadili et al. (2010) considered the 2 and 5 mm for total sentinel lymph node metastasis as the cutoff value, which could effectively predict the non-sentinel lymph node metastasis in melanoma patients. Wardwell-Ozgo et al. (2014) demonstrated that homeobox transcription factor A1 (HOXA1) mediated the cell invasion in melanoma cells, and primary tumors with high-expression HOXA1 were high-risk metastasis subgroups. Ferretti et al. (2016) found that BMI1 could be able to identify primary tumors that were likely to become metastatic, which was a key determinant of melanoma metastasis. This evidence concerns the gene HOXA1 and melanoma.