Calretinin

Calretinin (CR) is a calcium binding protein that has buffering calcium concentration, regulating neural signal transduction, and participating in hormone synthesis and other functions. In clinical practice, CR is applied in the diagnosis of various tumors. For example, CR is an important marker for malignant mesothelioma. It can be used to differentiate between thymic epithelioid mesothelioma (+) and lung adenocarcinoma (-). Meanwhile, the positive rate of CR in adrenocortical tumor is higher than that in benign pheochromocytoma, which makes it useful for assisting in differentiation. Moreover, CR can be expressed in testicular sex cord-stromal tumors such as Sertoli cell tumors, Leydig cell tumors, and granulosa cell tumors, but is also positive in some seminomas. Similarly, CR can exist in ovarian sex cord-stromal tumors, but is expressed in some epithelial tumors, which is associated with tumor proliferation, metastasis, and recurrence. In addition, CR expression level in ganglions and nerve fibers of congenital megacolon is significantly reduced compared to normal intestine, but the specific mechanism is still unclear.