Comparison of Dako HercepTest and Ventana PATHWAY anti-HER2 (4B5) tests and their correlation with silver in situ hybridization in lung adenocarcinoma

Prevalence and clinicopathological associations of HER2 expression in non-small cell lung cancer: a retrospective study in Jordanian patients

BACKGROUND

Human epidermal growth factor receptor 2 (HER2), a promising therapeutic target, can be mutated, amplified, or overexpressed in different malignancies, including non-small cell lung cancer (NSCLC). Although these alterations showed adverse prognostic effects in many cancers, their clinical significance in NSCLC is controversial. This study primarily assessed the prevalence of HER2 protein expression in NSCLC among Jordanian patients. In addition, the possible association between HER2 protein expression and clinicopathological variables was evaluated.

METHODS

A total of 100 surgically resected NSCLC cases treated at King Hussein Cancer Center (KHCC) between 2009 and 2021 were examined for HER2 protein expression using immunohistochemistry (IHC). The American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines for breast cancer were applied to interpret the results with a final score ranging from 0 to 3+, considering a score of 3 + as overexpression. Additionally, a separate subset of patients was tested for HER2 gene mutation. Fisher's exact test was used to assess the association between HER2 scores and the other variables. Kaplan-Meier method was used to calculate survival.

RESULTS

Of the 100 cases, Her2 overexpression (score 3+) was detected in 2 cases (2%), score 2 + in 10 cases (10%), score 1 + in 12 cases (12%), and score 0 in 76 cases (76%). The two positive cases were one adenocarcinoma and one squamous cell carcinoma; both patients were elderly male smokers. No significant association was identified between Her2 expression and age, gender, smoking, histological subtype, grade, stage, tumor size, and lymph node status. Our findings also showed no association between Her2 expression and survival; however, advanced tumor stages and positive lymph node metastasis were significantly associated with poor overall survival. All cases tested for the Her2 mutation were negative.

CONCLUSIONS

Her2 overexpression is uncommon in NSCLC among the Jordanian population. However, when the same scoring criteria are used, the rates are similar to other results found in Asian cohorts. Due to our study's relatively small sample size, a larger one is required to investigate the prognostic value and the molecular associations between the different Her2 alterations.

The Prospects of Using Structural Phase Analysis of Microcalcifications in Breast Cancer Diagnostics

The detection of microcalcifications in the breast by mammography is of great importance for the early diagnostics of breast cancer. This study aimed to establish the basic morphological and crystal-chemical properties of microscopic calcifications and their impact on breast cancer tissue. During the retrospective study, 55 out of 469 breast cancer samples had microcalcifications. The expression of the estrogen and progesterone receptors and Her2-neu showed no significant difference from the non-calcified samples. An in-depth study of 60 tumor samples revealed a higher expression of osteopontin in the calcified breast cancer samples (p ˂ 0.01). The mineral deposits had a hydroxyapatite composition. Within the group of calcified breast cancer samples, we detected six cases of colocalization of oxalate microcalcifications together with biominerals of the usual "hydroxyapatite" phase composition. The simultaneous presence of calcium oxalate and hydroxyapatite was accompanied by a different spatial localization of microcalcifications. Thus, the phase compositions of microcalcifications could not be used as criteria for the differential diagnostics of breast tumors.

Comparison of HercepTest™ mAb pharmDx (Dako Omnis, GE001) with Ventana PATHWAY anti-HER-2/neu (4B5) in breast cancer: correlation with HER2 amplification and HER2 low status

Performance of the new CE-IVD-marked HercepTest™ mAb pharmDx (Dako Omnis) assay (HercepTest (mAb)) was compared against the PATHWAY® anti-HER-2/neu (4B5) (PATHWAY 4B5) assay using 119 pre-selected breast cancer samples covering the entire range of HER2 immunohistochemistry (IHC) expression scores (0, 1 + , 2 + , 3 +). The sensitivity and specificity of both assays were assessed based on consensus IHC scores and amplification status, as determined by fluorescence in situ hybridization (FISH) according to 2018 ASCO/CAP testing guidelines. There was a high concordance between results from the HercepTest (mAb) and PATHWAY 4B5 assays for HER2-negative (IHC 0, 1 + , 2 + and FISH negative) and HER2-positive (IHC 3 + , 2 + and FISH positive) breast carcinomas (98.2%). Regarding individual IHC scores, complete agreement was achieved in 69.7% (83/119) of cases, and all but one of the discordant cases were due to higher HER2-status scoring using the HercepTest (mAb). Thus, more tumors were overscored as IHC 2 + by HercepTest (mAb) (27 versus 15) as evidenced by their lower FISH positivity rate (48.1% versus 80%). However, two amplified tumors identified as IHC 2 + by HercepTest (mAb) were missed by PATHWAY 4B5 (IHC 1 +). Four additional cases identified as IHC 2 + by HercepTest (mAb), with FISH ratio < 2 but elevated gene counts (≥ 4 to < 6), were recorded negative by PATHWAY 4B5. The HercepTest (mAb) detects HER2 expression with higher sensitivity in tumors with gene amplification (ISH group 1) and increased gene counts (ISH group 4) as well as in HER2-low tumors (HER2 IHC2 + /FISH negative or IHC 1 +). Future studies will demonstrate whether this translates into improved patient selection especially for new HER2-directed therapies.