[278] Evaluation of the Predictive Ability of a CK5/p63/CK8/18 Antibody Cocktail in Stratifying Breast Papillary Lesions (BPLs) on Needle Biopsy (NBx): An Algorithmic Approach Works Best
ES Reisenbichler, AL Adams, O Hameed. University of Alabama School of Medicine, Birmingham, AL
Background: We have previously found that breast papillomas (PAPs), atypical papillomas (APs) and (PCs) have different expression profiles as seen with a CK5/p63/CK8/18 antibody cocktail. The aim of this follow up study is to compare the utility of various components of this antibody cocktail in the evaluation of BPLs in NBx material.
Design: A series of 58 BPLs in NBx specimens were immunostained with a CK5/p63/CK8/18 antibody cocktail and evaluated without knowledge of the primary or the available follow up excisional biopsy (EBx) diagnosis (Dx) (32 PAPs, 7 APs and 19 PCs). Based on cutoffs obtained from our prior study, cases were characterized based on the presence or absence of a diffuse mosaic CK5/CK8/18 expression pattern with at least 20% CK5 positive cells, and on the presence or absence of at least a focal proliferative area with 80% or more CK8/18 positive cells. p63 expression was categorized as negative, diffuse (uniformly distributed staining in at least 1 myoepithelial cell per 10 non-peripheral epithelial cells), or intermediate (remainder). Using EBx Dx as the gold standard, we compared the sensitivity (Sn), specificity (Sp), positive (PPV) and negative predictive value (NPV) of the different markers, including an algorithmic approach (Figure) to predict a non-PAP diagnosis on EBx.
Results:
| Sn(%) [95% CI*] | Sp(%) [95%CI] | PPV(%) [95%CI] | NPV(%) [95%CI] | |
|---|---|---|---|---|
| Original Dx | 81 [60-93] | 91 [74-98] | 88 [67-97] | 85 [68-94] |
| CK8/18 alone | 100 [84-100] | 81 [63-92] | 81 [63-92] | 100 [84-100] |
| p63 alone | 96 [78-100] | 59 [41-76] | 66 [49-80] | 95 [73-100] |
| Algorithmic | 100 [84-100] | 94 [78-99] | 93 [75-99] | 100 [86-100] |
Conclusions: Compared to histology alone, differential CK5/8/18 expression, p63 expression, or an algorithmic approach using these markers in combination all have a higher Sn for a non-PAP diagnosis on EBx; however the algorithmic approach had the highest Sp and a 100% NPV. Use of a CK5/p63/CK8/18 antibody cocktail allows for more definitive classification of BPLs on NBx with the potential for more limited EBx procedures.
Category: Breast
Monday, March 9, 2009 9:30 AM
Poster Session I Stowell-Orbison/Autopsy Award # 45, Monday Morning