[304] Impact of Cold Ischemic Time on Estrogen Receptor, Progesterone Receptor, and HER2 Semi-Quantitative Immunohistochemical Scoring

Isil Z Yildiz-Aktas, David J Dabbs, Rohit Bhargava. University of Pittsburgh Medical Center

Background: There is a dearth of data regarding the acceptable limits of cold ischemic time (CIT) for breast tumors subjected to immunohistochemical(IHC) analysis for ER/PR/HER2. ASCO/CAP guidelines currently recommend a CIT of <1hour.
Design: Breast resection specimens were subjected to variable CIT periods (0.5, 1, 2, 3, 4, 24, and 48 hours) within the refrigerator and at room temperature. Hormone receptors were semi-quantitatively scored using H-score method. HER2 was scored using the ASCO/CAP guidelines. The results were compared to the core biopsy scores which have negligible CIT. Mild reduction in staining for hormone receptors was judged present if the H-score on the resection specimen was between one-half and three-fourth of the H-score at core biopsy. Significant reduction was judged present when the H-score on resection was less than one-half of the core biopsy H-score. Mild reduction in HER2 staining was judged present if there was one step discordance, and significant reduction was judged present if there was 2-step reduction in staining. A true reduction was judged present only when the reduction was consistently present for the increasing time interval. A focal reduction for a particular time sample was attributed to the heterogeneity of the tumor sample.
Results: The study included 26 cases, all of which had refrigerated samples. Non-refrigerated samples (samples at room temperature) were present on 24 cases. The reduction in staining for ER, PR, and HER2 is shown in table 1.

Table 1
 Mild reductionMinimum time to mild reductionSignificant reductionMinimum time to significant reduction
Refrigerated Sample ER8/26 (31%)4 hours (3 of 8 cases)6/26 (23%)4 hours (1 of 6 cases)
Non-refrigerated Sample ER9/24 (38%)2 hours (1 of 9 cases)8/24 (33%)2 hours (1 of 8 cases)
Refrigerated Sample PR6/26 (23%)0.5 hour (2 of 6 cases)4/26 (15%)4 hours (1 of 4 cases)
Non-refrigerated Sample PR8/24 (33%)0.5 hour (1 of 8 cases)6/24 (25%)2 hours (1 of 6 cases)
Refrigerated Sample HER22/26 (8%)4 hours (2 of 2 cases)0/26 (0%)No significant reduction
Non-refrigerated Sample HER210/24 (42%)3 hours (3 of 10 cases)2/24 (8%)24 hours (2 of 2 cases)

Conclusions: Non-refrigerated samples are affected more by prolonged CIT than refrigerated samples. CIT of as short as one-half hour may occasionally impact the IHC staining for PR. Significant reduction in IHC staining however; generally does not result until 4 hours for refrigerated samples and 2 hours for non-refrigerated samples. The ASCO/CAP guideline of CIT< 1 hour is a prudent guideline to follow.
Category: Breast

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 33, Monday Morning


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