[1189] Re-Evaluation of Immunohistochemical Markers in Endometrial Adenocarcinomas

Haiyan Liu, Hong Yin, Hanlin Wang, Fan Lin. Geisinger Medical Center, Danville, PA; UCLA Medical Center, Los Angeles, CA

Background: When working on a tumor of unknown origin, a metastatic adenocarcinoma from the endometrium may present a diagnostic challenge because of the inconsistent data from the literature and complicated immunostaining profiles for endometrial adenocarcinoma (EAD). In this study, we re-evaluate the expression of an extensive panel of biomarkers in endometrial adenocarcinomas using a single immunostaining system (Ventana XT).
Design: We immunohistochemically evaluated the expression of 1) epithelial markers (AE1/3, CAM5.2, CK7, CK20, CK17, CK19, CK903, EMA); 2) mucin gene products (MUC1, MUC2, MUC4, MUC5AC, MUC6); 3) tumor suppressor genes and transcription factors (ER, PR, p53, beta-catenin, ERG, GATA3, WT-1, CDX2, pVHL); and 4) tumor-associated proteins (TTF-1, napsin A, p16, HepPar1, glypican 3, SALL4, OCT4, PAX8, RCC, GCDFP15, mammaglobin, S100P, IMP3, maspin, MOC31, CEA, CA19-9, CD10, CD15, villin, and P504S) on 128 cases of endometrial adenocarcinoma endometrioid type (FIGO I 32 cases, FIGO II 58 cases, and FIGO III 38 cases) on tissue microarray sections. The staining intensity distribution was recorded.
Results: The positive staining results from selected antibodies are summarized in Table 1. Twelve of 128 cases (9.4%) showed diffuse (4+) and strong p16 positivity. All cases were negative for CK20, SALL4, OCT4, MUC2, HepPar1, villin, GCDFP15, and S100P.

Table 1. Summary of immunostaining results on selected antibodies

Antibody	EAD FIGO 1 (N=32)	EAD FIGO 2 (N=58)	EAD FIGO 3 (N=38)	Positive Cases (%)
CK7	29/32	52/58	34/38	89.8%
CK17	2/32	0/58	0/38	1.6%
MUC1	32/32	58/58	38/38	100%
Vimentin	31/32	52/58	35/38	92%
ER	32/32	58/58	35/38	97.7%
PR	30/32	57/58	38/38	97.7%
Mammoglobin	19/32	45/58	18/38	64%
TTF-1	0/32	2/58	0/38	1.6%
Napsin A	3/32	0/58	0/38	2.3%
Glypican 3	0/32	0/58	4/38	3%
pVHL	0/32	2/58	0/38	1.6%
Maspin	12/32	15/58	4/38	24%
CEA	4/32	9/58	5/38	14%
p16	32/32	57/58	38/38	99%
P504S	7/32	34/58	24/38	50.8%
CDX2	0/32	1/58	0/38	0.8%
PAX8	32/32	58/58	37/38	99%
RCC	0/32	4/58	2/38	4.7%
ERG	0/32	1/58	0/38	0.8%

Conclusions: These data demonstrate that 1) mammaglobin and other tumor/organ-specific markers can be positive in a significant percentage of cases; 2) nearly all cases are positive for ER, PR and PAX8 regardless of tumor grade; 3) 10% of cases can be negative for CK7 and vimentin; and 4) caution should be taken when using p16 to differentiate endometrial primary from endocervical primary since close to 10% of cases are diffusely and strongly positive for p16.
Category: Gynecologic & Obstetrics

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 201, Wednesday Afternoon