[972] Reevaluation of Expression of SALL4 and PAX8 in Carcinomas from Various Organs.

Myra Wilkerson, Jianhui Shi, Haiyan Liu, Jeffrey W Prichard, Fan Lin. Geisinger Medical Center, Danville, PA

Background: SALL4 and PAX8 are two recently described useful immunohistochemical markers. SALL4 is a sensitive and specific maker for germ cell tumors, including seminoma, embryonal carcinoma, and yolk sac tumor. PAX8 is a sensitive marker for thyroid carcinomas, ovarian serous carcinoma and renal cell carcinomas. However, the published data were limited and inconsistent. In this study, we attempted to re-evaluate the expression of SALL4 and PAX8 in a large series of carcinomas from various organs using a single immunostaining system (Ventana XT).
Design: Immunohistochemical evaluation of the expression of SALL4 (Cat. No CM384C; Biocare Medical) and PAX8 (Cat. No. CP379AK; Biocare Medical) on 872 cases of carcinomas from various organs using tissue mircroarray sections was performed. The staining intensity and the distribution were recorded.
Results: The positive staining results (%) and the total number of cases for each entity (N) are summarized in Table 1. Twenty-two cases of intratubular germ cell neoplasia (ITGCN) were also positive for SALL4. One case of carcinoma from each of the colon, esophagus, endocervix and ovary was positive for SALL4. Both SALL4 and PAX8 are negative for lung ADC (N=50), lung SCC (N=49), medullary thyroid CA (N=10), gastric ADC (N=21), Pancreatic ADC (N=50), urothelial CA (N=40), prostatic ADC (N=100), cholangiocarcinoma (N=11), breast ductal CA (N=110) and lobular CA (N=31), hepatocellular CA (N=18) and adrenal cortical neoplasm (N=24).

Table 1. Summary of immunostaining results

Tumor	SALL4 (%)	PAX8 (%)
Seminoma (N=30)	100	0
Embryonal CA (N=24)	100	0
Yolk sac tumor (N=12)	100	0
Papillary thyroid CA (PTC, N=45)	0	93
Follicular thyroid CA (FTC, N=36)	0	100
Anaplastic thyroid (ATC, N=5)	0	40
Clear cell RCC (N=36)	0	97
Papillary RCC (N=25)	0	100
Colonic ADC (N=38)	3	3
Esophageal ADC (N=30)	3	0
Endocervical ADC (N=17)	6	53
Ovarian serous CA (N=15)	6	100
Pancreatic endocrine neoplasm (PEN, N=15)	0	33

ADC-adenocarcinoma; CA-carcinoma; RCC-renal cell carinoma


Conclusions: Our data confirm that 1) SALL4 is a sensitive and specific marker for the diagnosis of germ cell tumors and ITGCN, with an exception that the positivity can be seen in rare cases of carcinoma of the colon, esophagus, endocervix and ovary; 2) PAX8 is a useful marker in the diagnosis of papillary and clear cell RCCs, PTC, FTC, and ovarian serous CA. Caution should be taken, as a high percentage of endocervical ADC, PEN, and rare colonic ADC can be positive for PAX8.
Category: Genitourinary (including renal tumors)

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 134, Wednesday Afternoon