Squamous cell carcinoma-related oncogene is highly expressed in developing, normal, and adenomatous adrenal tissue but not in aggressive adrenocortical carcinomas

Background. Our previous work has demonstrated squamous cell carcinoma-related oncogene (SCCRO) expression in adult marine adrenocortical tissue. The aim of this study was to assess patterns of SCCRO expression in the embryonic murine adrenal gland, and in normal and neoplastic human adrenocortical tissues in order to determine its role as a marker of differentiation in adrenocortical development and neoplastic progression. Methods. Murine embryos were procured at developmental stages E8 to E18. A tissue microarray was constructed containing 38 normal, 39 adenomalous, and 87 carcinomatous human adrenocortical specimens. Immunohistochemistry for SCCRO was performed and its expression was graded in suitable tissues. Results. SCCRO expression was detected in the marine adrenal cortex as early as E15 and persisted into the postnatal period. High-level SCCRO expression was identified in 94% of normal (32134) and adenomatous (29131) adrenocortical specimens but in only 63% (45172) of adrenocortical carcinoma (A CC) specimens (P =. 001). Loss of SCCRO expression in primary A CC (13134 (34%)) correlated with advanced stage (P 06), presence of M1 disease at presentation (P 03), and worse overall Survival (P =. 006). Conclusions. SCCRO appears to be a marker of adrenocortical differentiation in both marine and human systems. SCCRO expression may be useful in distinguishing adrenocortical adenomas from A CC. Moreover, loss of SCCRO expression in primary A CC is associated with worse outcome and may be a marker of progressive dedifferentiation in these tumors.