Diagnostic interobserver variability of atypia assessment in columnar cell lesions among a group of expert breast pathologists in the United Kingdom and the Republic of Ireland, on behalf of the UK national coordinating committee for breast pathology.

Aims: Atypical ductal hyperplasia and flat epithelial atypia (FEA) have defined diagnostic criteria, yet there is variation in the interpretation of these criteria, particularly when the atypia is present in a background of columnar cell lesions (CCLs). This study focuses upon cases which are especially challenging or difficult to classify reproducibly according to existing criteria.

Methods And Results: Thirteen breast pathology experts were asked to classify 10 challenging cases with CLLs as atypical or non-atypical.

Cell cycle traverse rate predicts long-term outcomes in a multi-institutional cohort of patients with triple-negative breast cancer.

Background: Ki67 index (KI) and mitotic index (MI) are proliferation markers with established prognostic value in breast carcinomas. While KI is evaluated immunohistochemically and reported as a percentage, MI is determined visually and reflects total mitotic cells in 10 high-power fields. Our objective was to integrate KI and MI into a novel metric; the cell cycle traverse rate (CCTR).

Hydroxyacid Oxidase 1, a Glutamine Metabolism-Associated Protein, Predicts Poor Patient Outcome in Luminal Breast Cancer.

Breast cancer (BC), which remains the most prevalent malignancy among women, is characterised by significant heterogeneity across its molecular subtypes. Oestrogen receptor-positive (ER+) (luminal) BC represents approximately 75% of cases, and despite advancements in treatment there remains around a 40% recurrence rate. Cellular uptake of glutamine is conducted by solute carriers (SLCs), which are significantly associated with outcome in luminal BC.

Protein Tyrosine Kinase 7 (PTK7) in Breast Cancer: A Retrospective Analysis of Tumour Expression and Association with Clinical Outcome.

Protein tyrosine kinase 7 (PTK7), originally known as colon carcinoma kinase (CCK4), is an evolutionary conserved, catalytically defective transmembrane receptor involved in Wnt signalling. PTK7 has been identified as a potential therapeutic target, and a PTK7 antibody drug conjugate (PF-06647020; cofetuzumab pelidotin) has been investigated in phase I clinical trials for triple-negative breast cancer, ovarian cancer, and non-small cell lung cancer. PTK7 protein expression was evaluated in 1136 early-stage invasive breast tumours by immunohistochemistry.

HER2-positive grade 1 invasive carcinomas of the breast.

Aims: The American Society of Clinical Oncology and College of American Pathologists HER2-guidelines recommend repeat testing for most grade 1 mammary carcinomas that are HER2-positive in the core biopsy. This study aimed to assess the value of repeat HER2-testing and the histological features of HER2-positive grade 1 carcinomas.

Methods And Results: A case-series of HER2-results of grade 1 carcinomas was conducted of patients with no pre-operative systemic treatment over a 5-year period.