E-cadherin 阴性乳腺淋巴上皮瘤样癌与 E-cadherin 阴性浸润性小叶癌的临床病理特征与预后比较分析

E-cadherin-negative breast lymphoepithelial-like carcinoma (E-Cad-neg BLEC) is a rare malignant tumor. To date, no study has compared the clinicopathological characteristics and prognosis between E-Cad-neg BLEC and E-Cad-neg invasive lobular carcinoma (ILC).

To clarify the relationship between E-Cad-neg BLEC and E-Cad-neg ILC, we analyzed 12 patients with E-Cad-neg BLEC, comparing their clinicopathological characteristics and tumor prognosis with those of 578 patients with E-Cad-neg classical invasive lobular carcinoma (c-ILC) or 43 patients with E-Cad-neg pleomorphic lobular carcinoma (PLC).

The results showed that E-Cad-neg BLEC was a diffuse, non-adherent tumor with pleomorphic growth. There was abundant lymphocyte infiltration in the tumor stroma. Lobular carcinoma in situ was observed around the tumor in 5 patients. Compared with E-Cad-neg c-ILC, E-Cad-neg BLEC had significantly lower expression levels of ER (p < 0.001), PR (p < 0.001), and HER2 (p = 0.029), and a higher Ki-67 proliferation index (p < 0.001). Compared with E-Cad-neg PLC, E-Cad-neg BLEC was less likely to exhibit vascular invasion (p < 0.001) and perineural invasion (p < 0.001), and had lower HER2 expression (p = 0.001). In terms of histo-molecular subtypes, E-Cad-neg BLEC was mainly triple-negative, while E-Cad-neg c-ILC and E-Cad-neg PLC were mainly luminal A and luminal B. Regarding prognosis, the prognosis curve of E-Cad-neg BLEC was close to that of E-Cad-neg c-ILC. Analysis of the percentage of tumor-infiltrating lymphocytes (TILs) revealed that in both E-Cad-neg c-ILC and E-Cad-neg PLC, higher TIL levels were associated with a poor prognosis, in contrast to the favorable prognosis observed in E-Cad-neg BLEC.

Our findings indicate that E-Cad-neg BLEC is a type of breast carcinoma characterized by extensive lymphocytic infiltration and high proliferative activity and is associated with a relatively favorable prognosis.