A woman with invasive lobular carcinoma of the breast shows bilateral 'shrinkage' pattern on MRI rather than a single mass. Which molecular characteristic of invasive lobular carcinoma explains its diffuse infiltrative growth pattern?
- A Loss of E-cadherin function due to CDH1 mutation ✓
- B Overexpression of HER2
- C BRCA2 germline mutation
- D Gain of MYC amplification
Explanation
Invasive lobular carcinoma is characterized by loss of E-cadherin (encoded by CDH1), a cell-cell adhesion molecule. E-cadherin loss disrupts the epithelial adherens junction complex, leading to cells that grow in single-file 'Indian file' rows through the stroma rather than forming cohesive glandular structures. This explains the diffuse infiltrative pattern, the characteristic 'targetoid' pattern around lobules, and the insidious clinical and radiological presentation with relative mammographic occultness. CDH1 germline mutations also predispose to hereditary lobular and diffuse gastric cancer.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.