Clinicopathological Study of Breast Carcinoma Patients with Equivocal HER2 Immunohistochemical Status: Five-Year Experience from a Tertiary Care Center.

Background and objectives: Assessment of HER2 gene status has central role in the management of breast cancer patients. For determining HER2 status, immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are the most commonly used tests. Immunohistochemistry scores of 3+ and 1+ were considered as HER2 positive and negative, respectively. On the other hand, HER2 equivocal cases need further confirmation by FISH test assessment. This study aimed to identify the clinicopathological characteristics of patients with HER2 equivocal tumors served by Sultan Qaboos University Hospital (SQUH) in Muscat, Oman, with emphasis on treatment plans and disease outcome. Methods: This was a retrospective cross-sectional study, which involved all breast cancer female patients who were referred to SQUH from 2016 to 2020. It included a total of 108 patients who were diagnosed with HER2 (2+) breast cancer. Patients' data were analyzed in relation to the subsequent FISH status. Results: During the study period, data from 108 females with HER2 2+ were collected; among them, 22 (20%) were FISH positive, 64 (59%) FISH negative, 17 (16%) FISH borderline and five (5%) with no results. Regarding patients' characteristics, 91.2% of all subjects had invasive ductal carcinoma, 93.2% expressed estrogen receptors and 77.6% progesterone receptor. Age, postmenopausal histopathology, tumor grade, TNM staging, ER, PR, Ki67, LVSI, NLR, treatment and follow-up did not show significant association with different FISH results. Conclusions: The majority of HER2 equivocal breast cancer cases were FISH negative. In trastuzumab chemotherapy, an association between different FISH results was expected.

Immunohistochemical expression of BCL-2 in hydatidiform moles: a tissue microarray study.

Background: Hydatidiform moles (HM) are members of gestational trophoblastic diseases (GTD) and, in some cases, might progress to gestational trophoblastic neoplasia (GTN). HMs are either partial (PHM) or complete (CHM). Some HMs are challenging in arriving at a precise histopathological diagnosis. This study aims to investigate the expression of BCL-2 by immunohistochemistry (IHC) in HMs as well as in normal trophoblastic tissues "products of conception (POC) and placentas" using Tissue MicroArray (TMA) technique. Methods: TMAs were constructed using the archival material of 237 HMs (95 PHM and 142 CHM) and 202 control normal trophoblastic tissues; POC and unremarkable placentas. Sections were immunohistochemically stained using antibodies against BCL-2. The staining was assessed semi-quantatively (intensity and percentage of the positive cells) in different cellular components (trophoblasts and stromal cells). Results: BCL-2 showed cytoplasmic expression in more than 95% of trophoblasts of PHM, CHM and controls. The staining showed a significant reduction of the intensity from controls (73.7%), PHMs (76.3%) to CHM (26.9%). There was a statistically significant difference between PHM and CHM in the intensity (p-value 0.0005) and the overall scores (p-value 0.0005), but not the percentage score (p-value > 0.05). No significant difference was observed in the positivity of the villous stromal cells between the different groups. All cellular components were visible using the TMA model of two spots/case (3 mm diameter, each) in more than 90% of cases. Conclusions: Decreased BCL-2 expression in CHM compared to PHM and normal trophoblasts indicates increased apoptosis and uncontrolled trophoblastic proliferation. Construction of TMA in duplicates using cores of 3 mm diameter can overcome tissue heterogeneity of complex lesions.

Neoadjuvant Chemotherapy Alters Neuropilin-1, PlGF, and SNAI1 Expression Levels and Predicts Breast Cancer Patients Response.

Circulating proteins hold a potential benefit as biomarkers for precision medicine. Previously, we showed that systemic levels of neuropilin-1 (NRP-1) and its associated molecules correlated with poor-prognosis breast cancer. To further identify the role of NRP-1 and its interacting molecules in correspondence with patients' response to neoadjuvant chemotherapy (NAC), we conducted a comparative study on blood and tissue samples collected from a cohort of locally advanced breast cancer patients, before and after neoadjuvant chemotherapy (NAC). From a panel of tested proteins and genes, we found that the levels of plasma NRP-1, placenta growth factor (PlGF) and immune cell expression of the transcription factor SNAI1 before and after NAC were significantly different. Paired t-test analysis of 22 locally advanced breast cancer patients showed that plasma NRP-1 levels were increased significantly (p = 0.018) post-NAC in patients with pathological partial response (pPR). Kaplan-Meier analysis indicated that patients who received NAC cycles and their excised tumors remained with high levels of NRP-1 had a lower overall survival compared with patients whose tissue NRP-1 decreased post-NAC (log-rank p = 0.049). In vitro validation of the former result showed an increase in the secreted and cellular NRP-1 levels in resistant MDA-MB-231 cells to the most common NAC regimen Adriyamicin/cyclophosphamide+Paclitaxel (AC+PAC). In addition, NRP-1 knockdown in MDA-MB-231 cells sensitized the cells to AC and more profoundly to PAC treatment and the cells sensitivity was proportional to the expressed levels of NRP-1. Unlike NRP-1, circulating PlGF was significantly increased (p = 0.014) in patients with a pathological complete response (pCR). SNAI1 expression in immune cells showed a significant increase (p = 0.018) in patients with pCR, consistent with its posited protective role. We conclude that increased plasma and tissue NRP-1 post-NAC correlate with pPR and shorter overall survival, respectively. These observations support the need to consider anti-NRP-1 as a potential targeted therapy for breast cancer patients who are identified with high NRP-1 levels. Meanwhile, the increase in both PlGF and SNAI1 in pCR patients potentially suggests their antitumorigenic role in breast cancer that paves the way for further mechanistic investigation to validate their role as potential predictive markers for pCR in breast cancer.