Canonical and noncanonical Hedgehog pathway in the pathogenesis of multiple myeloma

摘要

The Hedgehog (Hh) pathway regulates multiple processes involved in development and differentiation of tissues and organs during embryonic life. Recently, it has become evident that Hh signaling retains some activity even during adult life: in mature tissues, it regulates tissue homeostasis and repair and, in those tissues undergoing constant renewal, such as skin, colon, liver, and blood, it is also implicated in maintaining a stem/progenitor cell compartment, explaining how the Hh pathway deregulation may cause developmental defects during the embryonic life. Its abnormal activity can also lead to tumorigenesis during adult life either by stem cell pool expansion or mutations affecting the normal growth-regulatory mechanisms.