ER positive + HER-2 negative

Tumor sequencing confirmed both germline variants but showed microsatellite stability and no loss of heterozygosity, arguing against a causal role of MSH6. This case illustrates how PRS, in combination with moderate-risk variants, like those in CHEK2, may drive early-onset MBC and highlights the need to incorporate polygenic models into risk assessment and counseling.

Within an ER+/HER2- BC cohort, higher parity seems to be associated with a higher prevalence of pure ILC. No association was found between parity and clinicopathological features of ER+/HER2- pure ILC.

Diffuse gastrointestinal involvement by invasive lobular carcinoma is uncommon and may mimic inflammatory, infectious, ischemic, or medication-related conditions, contributing to delayed diagnosis. This case highlights an important diagnostic pitfall and underscores the need to consider metastatic disease in patients with a history of lobular breast carcinoma who present with unexplained gastrointestinal symptoms, even in the absence of radiographically apparent disease.

NPI, using a threshold of 3.4 as recommended by NICE, may assist in identifying patients for whom Oncotype DX testing could be considered. Ki-67 may provide additional prognostic context when interpreted alongside NPI. These markers may contribute to broader risk stratification frameworks but should be viewed as complementary to genomic testing.

P3, N=3902, Recruiting, UNICANCER | Not yet recruiting --> Recruiting

 Approximately one (20.2 %) in five patients with early-stage, clinically node-negative ILC harbors occult axillary nodal metastases. Pathologic tumor size emerged as the primary determinant of nodal involvement. Pleomorphic variants showed a tendency toward higher nodal burden. These findings indicate that omission of SLNB in ILC may carry a risk of axillary understaging with potential therapeutic implications. Pending evidence from prospective studies specifically designed for lobular histology, SLNB should continue to be considered an essential component of axillary evaluation in this subgroup.

P2, N=81, Active, not recruiting, National Cancer Institute (NCI) | Trial completion date: Feb 2026 --> Feb 2027

In this ITC analysis of patient-level data from three phase III trials, although not powered for formal hypothesis testing, the all-oral targeted combination therapy imlunestrant + abemaciclib showed a consistent numerical reduction in the risk of disease progression or death compared with fulvestrant + abemaciclib in patients with ER-positive/HER2-negative ABC previously treated with endocrine therapy ± CDK4/6i.

P3, N=263, Completed, Sun Yat-sen University | Active, not recruiting --> Completed

P3, N=2288, Not yet recruiting, Fudan University

Tamoxifen reduces the long-term risk of distant recurrence in both luminal A and B tumors, although timing of benefit varies by subtype. Even after treatment, patients with luminal tumors have a substantial late risk, highlighting the need for long-term follow-up.