201. Effects of degreasing pretreatment on immunohistochemistry and molecular analysis of gastrointestinal and breast cancer samples.
- Author
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Jin S, Wu, Zhang Y, Tang H, Yu J, Zhang J, Li X, Liu Y, Yang J, Zhang T, Hu M, Li X, Xiao S, Yue J, and Wang M
- Abstract
Lymph node status is a key factor in determining stage, treatment, and prognosis in cancers. Small lymph nodes in the fat-rich gastrointestinal and breast cancer specimens are easily missed in conventional sampling methods. This study examined the effectiveness of degreasing pretreatment with dimethyl sulfoxide (DMSO) in lymph node detection and its impact on the analysis of clinical treatment-related proteins and molecules. Thirty-three cases of gastrointestinal cancer specimens from radical gastrectomy and 63 cases of breast cancer specimens from modified radical mastectomy were included. After routine sampling of lymph nodes, the specimens were immersed in DMSO for 30 minutes for defatting. We assessed changes in the number of detected lymph nodes and pN staging in 33 gastrointestinal cancer specimens and 37 breast cancer specimens. Additionally, we analyzed histological characteristics, Masson's trichrome special staining, and immunohistochemistry (gastrointestinal cancer: MMR, HER2, PD-L1; breast cancer: ER, PR, AR, HER2, Ki-67, PD-L1). Molecular status was evaluated for colorectal cancer (KRAS, NRAS, BRAF, MSI) and breast cancer (HER2) in gastrointestinal cancer specimens and the remaining 26 breast cancer specimens. Compared to conventional sampling, DMSO pretreatment increased the detection rate of small lymph nodes (gastrointestinal cancer: p<0.001; breast cancer: p<0.001) and improved pN staging in one case each of gastric cancer, colon cancer, and rectal cancer (3/33, 9.1%). No significant difference in the morphology, special staining, protein, and molecular status of cancer tissue after DMSO treatment were found. Based on these results and our institutional experience, we recommend incorporating DMSO degreasing pretreatment into clinical pathological sampling practices., (Copyright © 2024. Published by Elsevier Inc.)
- Published
- 2024
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