<i>GHSR</i>methylation‑dependent expression of a variant ligand and receptor of the ghrelin system induces thymoma tumorigenesis

Our previous study reported that the DNA methylation of growth hormone secretagogue receptor (GHSR) was significantly higher in thymoma or thymic carcinoma (TC) than normal tissue samples. Thymic epithelial tumors (TETs) with GHSR were associated worse prognosis those lower levels methylation. Diversified components ghrelin‑GHSR axis may exert opposing effects cancer progression, depending on type question. However, precise function remains unclear. In present study, mRNA expression five key ghrelin system [native ligand ghrelin, variant In‑1 native GHSR1a, GHSR1b and acylation enzyme O‑acyltransferase (GOAT)] examined 58 TET samples by reverse transcription‑quantitative PCR, protein GHSR1a assessed 20 TETs using immunohistochemistry. The results revealed (variant forms) GOAT more strongly expressed compared thymic‑adjacent tissue. By contrast, no significant differences observed (native between positively a relationship not found thymoma. Immunohistochemical analysis generally correlated corresponding protein, increased advanced‑stage TETs. These indicate is shift from (ghrelin GHSR1a) to (In‑1 GHSR1b), which induces tumorigenesis thymoma, but TC.