Interobserver Variation in the Assessment of Immunohistochemistry Expression Levels in HER2-Negative Breast Cancer: Can We Improve the Identification of Low Levels of HER2 Expression by Adjusting the Criteria? An International Interobserver Study.

The classification of human epidermal growth factor receptor 2 (HER2) expression is optimized to detect HER2-amplified breast cancer (BC). However, novel HER2-targeting agents are also effective for BCs with low levels of HER2. This raises the question whether the current guidelines for HER2 testing are sufficiently reproducible to identify HER2-low BC.

Gene Expression in Ductal Carcinoma In Situ and Synchronous Invasive Breast Cancer.

The underlying mechanism of the progression of ductal carcinoma in situ (DCIS), a non-obligate precursor of invasive breast cancer (IBC), has yet to be elucidated. In IBC, Apolipoprotein B mRNA Editing Enzyme, Catalytic Polypeptide-Like 3B (APOBEC3B) is upregulated in a substantial proportion of cases and is associated with higher mutational load and poor prognosis. However, APOBEC3B expression has never been studied in DCIS.

Promoter hypermethylation in ductal carcinoma in situ of the male breast.

Ductal carcinoma in situ (DCIS) of the male breast is very rare and has hardly been studied molecularly. In males, we compared methylation status of 25 breast cancer-related genes in pure DCIS (n = 18) and invasive breast carcinoma (IBC) with adjacent DCIS (DCIS-AIC) (n = 44) using methylation-specific multiplex ligation-dependent probe amplification. Results were compared to female breast cancer (BC).

Copy number profiling of oncogenes in ductal carcinoma of the male breast.

Characterizing male breast cancer (BC) and unraveling male breast carcinogenesis is challenging because of the rarity of this disease. We investigated copy number status of 22 BC-related genes in 18 cases of pure ductal carcinoma (DCIS) and in 49 cases of invasive carcinoma (IC) with adjacent DCIS (DCIS-AIC) in males using multiplex ligation-dependent probe amplification (MLPA). Results were compared to female BC and correlated with survival.

Gene Expression Differences between Ductal Carcinoma in Situ with and without Progression to Invasive Breast Cancer.

To understand the molecular alterations driving the progression of ductal carcinoma in situ (DCIS), we compared patients with pure DCIS and patients with DCIS and synchronous invasive breast cancer (IBC). Twelve patients with extensive pure DCIS were included as a representation of indolent lesions with limited invasive capacity. These cases were matched with 12 patients with a limited DCIS component and IBC, representing lesions with a high invasive potential.

Male breast cancer precursor lesions: analysis of the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program.

In men, data regarding breast cancer carcinogenesis are limited. The aim of our study was to describe the presence of precursor lesions adjacent to invasive male breast cancer, in order to increase our understanding of carcinogenesis in these patients. Central pathology review was performed for 1328 male breast cancer patients, registered in the retrospective joint analysis of the International Male Breast Cancer Program, which included the presence and type of breast cancer precursor lesions.

Extent of ductal carcinoma in situ according to breast cancer subtypes: a population-based cohort study.

Ductal carcinoma in situ (DCIS) is a precursor of invasive breast carcinoma (IBC). The DCIS component is often more extensive than the invasive component, which affects local control. The aim of our study was to analyze features of DCIS within different IBC subtypes, which may contribute to the optimization of personalized approaches for patients with IBC.