[721] SATB2 Double-Staining: Significant Improvement in Specificity for Colonic Adenocarcinoma

Jonathan Rock, Rachel Roth, Amy Lehman, William Marsh, Wendy L Frankel. Ohio State University Wexner Medical Center, Columbus, OH

Background: The high prevalence of colonic adenocarcinoma (Ad) in the US has made the distinction of metastatic colon Ad from other primaries a commonly encountered clinical problem. The immunohistochemical (IHC) stains CDX2, CK20 and Villin are commonly used for this distinction with well-established sensitivities and specificities for each. Small biopsies or cytologic specimens limit the number of stains that may be attempted. The transcription factor SATB2 has been proposed as a potentially sensitive and specific marker for colonic Ad. To define the utility of SATB2 as a nuclear marker in double-stains (DS), we evaluated its sensitivity and specificity compared to CDX2 when combined with cytoplasmic stains CK20 and Villin.
Design: Tissue microarrays with 1 mm cores were made from right-sided colon Ad (222), breast Ad (45), hepatocellular carcinoma (67), lung Ad (32), ovarian Ad (18), neuroendocrine carcinoma (32), pancreatic Ad (40), prostate Ad (45) and gastric Ad (78). IHC DS were performed pairing CDX2 and SATB2 each with CK20 and Villin. Staining was graded as positive or negative, with a 5% threshold. DS were considered positive only when both nuclear and cytoplasmic staining was >5%. Sensitivity and specificity were calculated and compared using McNemar's test for paired comparisons.
Results:

Stain Performance for Colonic Ad vs. Other Primaries
StainSensitivitySpecificityOverall % Correct
CDX20.99 (0.97, 1.00)0.85 (0.80, 0.88)0.90 (0.87, 0.92)
SATB20.95 (0.92, 0.98)0.88 (0.84, 0.91)0.91 (0.88, 0.93)
Villin0.97 (0.94, 0.99)0.56 (0.51, 0.61)0.71 (0.67, 0.75)
CK200.93 (0.89, 0.96)0.79 (0.74, 0.83)0.84 (0.81, 0.87)
CDX2 + CK200.92 (0.88, 0.95)0.93 (0.89, 0.95)0.92 (0.90, 0.95)
CDX2 + Villin0.96 (0.93, 0.99)0.88 (0.84, 0.91)0.91 (0.90, 0.93)
SATB2 + CK200.90 (0.86, 0.94)0.98 (0.96, 0.99)0.95 (0.93, 0.96)
SATB2 + Villin0.93 (0.89, 0.96)0.97 (0.94, 0.98)0.95 (0.93, 0.97)
(95% CI)

CDX2 and SATB2 performed similarly and were the best overall single stains with CDX2 more sensitive and SATB2 more specific. DS significantly improved specificity over any single counterpart. While DS with CK20 and Villin varied in sensitivity and specificity, there was little difference in overall % correctness. DS with SATB2 showed similar sensitivities to those with CDX2, but statistically improved specificity.
Conclusions: SATB2 shows excellent sensitivity and specificity for colon Ad. When utilized in DS, SATB2 and CK20 are the most specific combination for colon Ad. The efficacy of SATB2 in DS makes it a valuable addition to existing IHC panels for identification of colon Ad particularly in evaluation of small biopsies.
Category: Gastrointestinal

Monday, March 4, 2013 1:00 PM

Poster Session II # 131, Monday Afternoon

 

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