The Genomic Landscape of Invasive Lobular Breast Cancer

Invasive lobular carcinoma of the breast (ILC) is the most common histologic subtype (15% of cases) after invasive ductal carcinoma. Aside from a distinct morphologic appearance, ILC is usually characterized by expression of the estrogen receptor, lack of HER2 amplification, and the absence of E-cadherin (CDH1).

To examine the clinical implications of genomic alterations in ILC, investigators analyzed deletions, insertions, and substitutions in 360 cancer-related genes from 413 ILC primary tumors selected from four biobanks in Europe. They also performed copy number analyses in 170 samples and analyzed germline DNA in uninvolved lymph-node tissue from 196 patients. They then correlated the findings with clinical and pathologic features and o…