Comparison of adipophilin and recently introduced PReferentially expressed Antigen in MElanoma immunohistochemistry in the assessment of sebaceous neoplasms: A pilot study

Abstract

Background We and others have noticed consistent staining of sebaceous glands with PReferentially expressed Antigen in MElanoma (PRAME). We aimed to determine whether PRAME was as sensitive, specific, and interpretable as adipophilin for distinguishing sebaceous neoplasms (SNs) from other neoplasms. Methods Twenty SNs and 32 control cases were stained for PRAME and adipophilin. Extent of staining was scored as follows: 0, no staining; 1, <5% positivity; 2, 5% to 50% positivity; and 3, >50% positivity. Intensity was scored as negative, weak, moderate, or strong. A composite score was determined by adding the scores for extent and intensity. Results PRAME had positive composite scores in all 20 SNs in the more differentiated areas, whereas adipophilin had positive composite scores in 19/20 cases. PRAME showed positivity in the basaloid cells in 15/16 cases, whereas adipophilin was positive in 14. Among controls, PRAME and adipophilin had positive composite scores in 3/32 cases and 6/32 cases, respectively. Conclusions PRAME and adipophilin are comparable in terms of distribution and intensity for staining sebocytes. In the basaloid cells, PRAME expression is often more diffuse and easier to detect than adipophilin. In comparing the SNs to the controls, PRAME was more sensitive and more specific than adipophilin. PRAME could be used as an additional marker of sebaceous differentiation in everyday practice.

Cytoplasmic expression of PMS2 (clone EP51), PRAME, and STAT6 (clone YE361) as a potential immunohistochemical finding for detection of sebocyte differentiation

“…However, as stated in Donnell's paper, 1 cytoplasmic staining is observed in normal (Figure 1D) and neoplastic (Figure 1I) sebocytes (but not in other cell types), similar to the staining pattern of adipophilin and PMS2 (EP51). Unlike in Donnell's study, 1 PRAME was not superior to adipophilin for the detection of sebocyte differentiation in our study.…”

“…The study was conducted according to the Declaration of Helsinki and has been approved by the research ethics committee of the Shizuoka Cancer Center Hospital, Sunto, Japan (Ref: J2020-43). Keisuke Goto MD 1,2,3,4,5,6,7 Takashi Sugino MD, PhD 1 1…”

“…In this study, PRAME expression was often more diffuse and easier to detect than adipophilin, particularly in the basaloid tumor cells of sebaceous neoplasms. 1 We also detected the cytoplasmic immunostaining of postmeiotic segregation increased 2 (PMS2) (clone EP51) and signal transducer and activator of transcription 6 (STAT6) (clone YE361) as well as PRAME on normal sebocytes and tumor cells with sebocyte differentiation. Thus, we investigated the diagnostic utility of PMS2, PRAME, and STAT6, to detect sebocyte differentiation, by comparison with the classic marker adipophilin.…”

“…It may be because of the difference between PRAME antibody dilution (1:1000) in our study and that (1:50) in Donnell's study. 1 STAT6 immunohistochemistry is widely utilized in the diagnosis of solitary fibrous tumor because detection of nuclear STAT6 expression provides a highly sensitive and specific assay for this tumor type. 4 Like adipophilin, PMS2, and PRAME, STAT6 can also be expressed in the cytoplasm of normal sebocytes and their tumor cells.…”

PRAME expression in cellular neurothekeoma: A study of 11 cases

“…Among positive cases, Merkel cell carcinoma showed the highest intensity and percentage of positive cells. Another recent study 23 found positive expression of PRAME in a series of 20 sebaceous carcinomas.…”