RHOBTB2 and osteosarcoma: Expression of RHOBTB2, the first member of the family to be proposed as a candidate tumor suppressor gene, has been found decreased in breast [6,24,25], lung [26], bladder [27,28], and stomach [29] cancers, in osteosarcomas [30], as well as in cell lines derived from breast, lung [6], and bladder [27] tumors, and HNSCCs (head and neck squamous cell carcinomas) [31].