Cancer is a devastating disease and the depth study is also keeping pace with its spread. Signal transduction holds an important key to the origin and propagation of cancers. Among all other protein involved in proliferation of cell, RhoGTPase rac1 is also involved. This book highlights the recent advances made in the field with special emphasis on key regulators of signal transduction. This book also showcases the results of the study taken in looking at the expression pattern of cancers.