GRB7 and esophageal squamous cell carcinoma: On the other hand, although several studies have reported the oncogenic role of GRB7 expression in ESCC cells [13–15], few studies have focused on CNAs of GRB7. GRB7 is an adaptor protein that relays signals from cell surface receptors to specific downstream signaling cascades via protein-protein interactions of a variety of tyrosine kinases with its Src-homology 2 (SH2) domain [38–40].