Invasive lobular breast cancer (ILC) is the second most common histological breast cancer subtype, after invasive ductal breast cancer (IDC). ILC accounts for approximately 10% to 15% of all breast cancers, with approximately 24 000–36 000 cases annually in the US only. The hallmark of ILC is loss of E-cadherin (CDH1), resulting in discohesive cancer cells that infiltrate the breast stroma in a single-file pattern (1). Unique clinical features that differentiate ILC from IDC include more frequent multifocal disease, growth patterns often resulting in higher stage at presentation, positive resection margins necessitating completion mastectomy (2–5), and metastatic sites (6,7). Despite better prognostic factors (eg, more estrogen receptor [ER]+, and lower levels of the proliferation marker Ki67), there is increasing evidence that patients with ILC have worse long-term outcome compared with those with IDC (8–10). Finally, recent studies by The Cancer Genome Atlas (TCGA) (11) and Rationale Therapy for Breast Cancer (12) consortia have demonstrated differences between the genetic make-up of ILC and IDC and—of relevance here—have consistently identified an “immune-related” ILC transcriptomic subtype.

中文翻译：

---

为侵袭性小叶乳腺癌打开免疫肿瘤学研究之门

侵袭性小叶性乳腺癌（ILC）是仅次于侵袭性导管性乳腺癌（IDC）的第二大最常见的组织学乳腺癌亚型。ILC约占所有乳腺癌的10％至15％，仅在美国每年约有24 000–36 000例。ILC的标志是E-钙粘蛋白（CDH1），从而导致多歧性癌细胞以单排模式浸润乳腺基质（1）。使ILC与IDC区别开来的独特临床特征包括更常见的多灶性疾病，生长模式通常导致就诊时的较高分期，阳性切缘需要完成乳房切除术（2-5）和转移部位（6,7）。尽管有更好的预后因素（例如，更多的雌激素受体[ER] +和较低的增殖标志物Ki67水平），但越来越多的证据表明，与IDC相比，ILC患者的长期预后较差（8-10）。最后，