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Altered Rb, p16, and p53 expression is specific for porocarcinoma relative to poroma
Author(s) -
Zahn Joseph,
Chan May P.,
Wang Grace,
Patel Rajiv M.,
Andea Aleodor A.,
Bresler Scott C.,
Harms Paul W.
Publication year - 2019
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.13480
Subject(s) - cdkn2a , pathology , staining , immunohistochemistry , suppressor , cancer research , tumor suppressor gene , mutation , biology , medicine , gene , carcinogenesis , genetics
Background Porocarcinomas are rare aggressive carcinomas that harbor tumor suppressor mutations and must be distinguished from benign entities such as poromas. Methods To determine whether altered expression of these genes was diagnostically informative, we examined p53, Rb, and p16 staining patterns in 15 poromas and 16 porocarcinomas. Results Poromas consistently displayed diffuse strong expression of Rb in all but one case that displayed focal loss (1/15, 7%), and no evidence of aberrancy in p53 or p16. Porocarcinomas displayed diffuse or focal loss of Rb expression in 9/16 (56%) cases, diffuse loss or overexpression of p53 in 8/15 (53%), and diffuse loss or overexpression of p16 in 6/14 (43%). Diffuse aberrancy in p53 and Rb expression correlated with tumor mutations in TP53 and RB1 , respectively, whereas focal Rb loss was associated with wild type RB1 . Diffuse p16 overexpression correlated with Rb loss rather than CDKN2A mutation. For porocarcinomas with all three stains evaluable, 10/13 (77%) displayed aberrancy in at least one marker. Conclusions Our findings suggest that altered p53, p16, and/or Rb expression is relatively specific to porocarcinoma in comparison with poroma. Technical limitations of this panel, including possible focal Rb loss, must be kept in mind, especially in limited samples.