The Ca/calmodulin dependent protein kinases (CaMKs) are multifunctional serine/threonine kinases whose activity are regulated through Ca ²⁺ signaling. It is multifunctional best known for its critical role in learning and memory. Recent studies demonstrates that high levels of different isoform of CaMK, especially for CaMKII, expresses in several cancers such as lung, breast, prostate and colon cancer. CaMKII phosphorylates nearly 40 different proteins, including enzymes, ion channels, kinases, and transcription factors and plays a critical role in the regulation of proliferation, differentiation and survival of various cancer cells.