ALCAM and cancer: The first stage involves ALCAM overexpression during invasion of the dermis layers (depth of infiltration) by nests of cancer cells (which may be formed as a result of homophilic ALCAM-ALCAM interactions) (local growth stage), while the second stage involves decreased ALCAM expression which facilitates invasion of single cells and formation of metastatic foci in regional lymph nodes, which greatly worsens prognosis.