Assessment of HER2 status in breast cancer biopsies is not affected by accelerated tissue processing

Comparison between core needle biopsy and excisional biopsy for breast neoplasm

This study aimed to explore clinical significance of core needle biopsy (CNB) in pathological diagnosis of breast neoplasm.Seventy one breast neoplasm samples were obtained from Tongzhou Maternal and Child Health Hospital of Beijing between the years of 2006 and 2014. Forty five specimens were obtained via CNB and cases offering 26 of them received neoadjuvant chemotherapy. Pathology, histology, and immunohistochemistry results were compared between CNB specimens and excisional biopsy.Upward and downward tendencies could be observed in CNB specimens and excisional biopsy, respectively, in all items. Tumor proportion of CNB tissues was (33 + 2)/45 = 77.78%, when ductal carcinoma in situ detected by both CNB and excisional biopsy was 31/45 = 68.89%, with a consistency of (31 + 3)/45 = 75.56%. Tumor thrombus detected by both CNB and excisional biopsy was 2/45 = 4.44%. Among cases receiving neoadjuvant chemotherapy, CNB and excisional biopsy, in mitotic figure, cytological scoring and histological grading, showed a total change rate of >50% (50%-75%), while changes in duct and cellular heteromorphism were not distinct. Cases showing changes were up to 73.08%, with 8/26 = 30.77% for rise and 11/26 = 42.31% for descent.CNB could be used for preoperative diagnosis of breast neoplasm, and help to determine proper treatment regimen, thus elevating the rate of breast conserving. However, this method still has several limitations, particularly in immunohistochemical tests of human epidermal receptor protein-2. Neoadjuvant chemotherapy may influence the accuracy of CNB diagnosis.

The impact of pre-analytical parameters on class II biomarkers by immunohistochemistry: concordance across four tissue processing protocols

In the modern era of precision medicine, a number of class II immunohistochemistry (IHC) biomarkers are routinely tested in pathologic laboratories to select cancer patients who may be candidates for hormonal, targeted, and immune therapies. Pre-analytical factors, including tissue processing, are critical components of biomarker testing and require validation to ensure reliable results. In this study, we aimed to study the impact of tissue processing on biomarkers (including ER, PR, HER2, mismatch repair (MMR) proteins, BRAF V600E, and PD-L1) in a large prospective cohort of 109 tumors. We found that ER and MMR were not impacted; PR, HER2, and BRAF V600E were minimally affected; and PD-L1 regardless of the antibody clone was strongly influenced by a combination of tissue processing procedures and intratumoral heterogeneity. Our findings suggest that validation of pre-analytical parameters, such as tissue processing, is important for certain class II biomarkers, in particular PD-L1 IHC.

Accelerated Tissue Processing With Minimal Formalin Fixation Time for 9-Gauge Vacuum-Assisted Breast Biopsy Specimens

Objectives

Vacuum-assisted biopsy (VAB) of the breast seems unsuitable for rapid processing due to large size. We tested microwave-based acceleration.

Methods

As a proof-of-principle study, 9-gauge VAB specimens were taken from eight mastectomy specimens. Forty-two biopsy specimens were processed. Quality of H&E was evaluated in 84 slides, and estrogen receptor (ER), progesterone receptor (PR), E-cadherin, and human epidermal growth factor receptor 2 (HER2) stains were evaluated in six slides. Preoperative biopsy specimens were used as a control.

Results

Diagnostic quality of H&E slides was good in 87%, reasonable in 12%, and low in 1%. Quality of E-cadherin was good in 75% and reasonable in 25%. Quality of ER was good in 83% and reasonable in 17%. PR and both HER2 immunohistochemistry and fluorescence in situ hybridization were good in all slides. Quality of experimental slides was similar to control slides.

Conclusions

Nine-gauge VAB specimens can be processed within 4 hours. Slides are suitable for all routine pathologic stains. This enables a same-day diagnosis.

HER2, chromosome 17 polysomy and DNA ploidy status in breast cancer; a translational study

Breast cancer treatment depends on human epidermal growth factor receptor-2 (HER2) status, which is often determined using dual probe fluorescence in situ hybridisation (FISH). Hereby, also loss and gain of the centromere of chromosome 17 (CEP17) can be observed (HER2 is located on chromosome 17). CEP17 gain can lead to difficulty in interpretation of HER2 status, since this might represent true polysomy. With this study we investigated whether isolated polysomy is present and how this effects HER2 status in six breast cancer cell lines and 97 breast cancer cases, using HER2 FISH and immunohistochemistry, DNA ploidy assessment and multiplex ligation dependent probe amplification. We observed no isolated polysomy of chromosome 17 in any cell line. However, FISH analysis did show CEP17 gain in five of six cell lines, which reflected gains of the whole chromosome in metaphase spreads and aneuploidy with gain of multiple chromosomes in all these cases. In patients' samples, gain of CEP17 indeed correlated with aneuploidy of the tumour (91.1%; p < 0.001). Our results indicate that CEP17 gain is not due to isolated polysomy, but rather due to widespread aneuploidy with gain of multiple chromosomes. As aneuploidy is associated with poor clinical outcome, irrespective of tumour grade, this could improve future therapeutic decision making.