RPSAP52 and cancer: It is much more weakly expressed in ostb, in accord with its negative effects on ostb formation from MSC.(50) The need for tight control of HMGA2 expression is evidenced by its unusually complex regulatory circuitry including the cancer‐associated let‐7 miRNA and the HMGA2‐overlapping pseudogene RPSAP52 and the anti‐sense gene HMGA2‐AS1.