Homeobox (HOX) genes, coding for transcription factors, are located in clusters in chromosomes and are important for defining body segment boundary. HOX genes show specific expression pattern in correspondent body part, and their expressions also represent the location information of an adult cell. HOX genes take important role in cancer initiation and progression. Researches on HOX in leukamia have contituously been concerned, while researches on HOX in solid tumors, including lung cancer, gastrointestinal cancer, breast cancer and prostate cancer gain growing attention recently. It is of great importance to illustrate HOX expression regulation, cellular level function and transcriptional activity regulation for clarifying the role of HOX in cancer.