[1777] Expression of Calretinin and CK5/6 in Cholangiocarcinoma

Lanjing Zhang, Renee Frank, Emma E Furth, Amy F Ziober, Viginia A LiVolsi, Paul J Zhang. University Medical Center at Princeton, Princeton, NJ; University of Pennsylvania Medical Center, Philadelphia, Philadelphia, PA

Background: One of the mesothelial lineage markers, mesothelin, has been found expressed in, and a potential treatment target of, cholangioacarcinoma (CC). It raises the possibility that CC may be derived from cells sharing or switching to mesothelial phenotype. However, the expression of other mesothelial markers in CC is largely unknown.
Design: Twenty three well documented CC cases were retrieved from the archive of our institution. Immunohistochemical study of Calretinin (DC8), WT1 (6F-H2), D2-40, CK5/6 (D5/16 B4) and CK19 (b170) was done on formalin fixed paraffin embedded sections from each case using standard immunohistochemical protocols. We compared the protein expression levels between CC and normal bile duct (NBD) on the same block.
Results: All of the CC and BD are positive for CK19 (23/23), and all or mostly negative for WT1 (0/23) and D2-40 (1/23). Interestingly, calretinin immunoreactivity was detected in 52.2% (12/23) of CC, but not in NBD (0/23). CK5/6 was also detectable in 73.9% (17/23) of CC as well as all NBD (23/23) (Table).

Expression of Calretinin and CK5/6 in cholangiocarcinoma
Positive (total)12 (52.2%)017 (73.9%)23 (100%)
1+4 (17.4%)06 (26.1%)2 (8.7%)
2+4 (17.4%)04 (17.4%)6 (26.1%)
3+4 (17.4%)07 (30.4%)15 (65.2%)
Total23 (100%)23 (100%)23 (100%)23 (100%)
CC: cholangiocarcinoma; NBD: normal bile duct; 1+: 1-25% cells stained; 2+: 26-75% cells stained; 3+: >76% cells stained.

Conclusions: Significant numbers of CC could express calretinin and CK5/6, two of the commonly used mesothelial markers. Calretinin and CK5/6 immunoreactivities should be interpreted with caution in cases with differential diagnoses of mesothelioma or adenomatous tumor versus CC (either metastatic or primary). A full mesothelioma panel, including WT1 and/or D2-40 as shown in this study, should be used to better define a mesothelial lineage. The biology of this partial mesothelial phenotype in CC is unclear but might also be useful in differentiating CC from other adenocarcinomas.
Category: Liver

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 234, Tuesday Afternoon


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