SF3A2 promotes progression and cisplatin resistance in triple-negative breast cancer via alternative splicing of MKRN1.

Triple-negative breast cancer (TNBC) is the deadliest subtype of breast cancer owing to the lack of effective therapeutic targets. Splicing factor 3a subunit 2 (SF3A2), a poorly defined splicing factor, was notably elevated in TNBC tissues and promoted TNBC progression, as confirmed by cell proliferation, colony formation, transwell migration, and invasion assays. Mechanistic investigations revealed that E3 ubiquitin-protein ligase UBR5 promoted the ubiquitination-dependent degradation of SF3A2, which in turn regulated UBR5, thus forming a feedback loop to balance these two oncoproteins. Moreover, SF3A2 accelerated TNBC progression by, at least in part, specifically regulating the alternative splicing of makorin ring finger protein 1 (MKRN1) and promoting the expression of the dominant and oncogenic isoform, MKRN1-T1. Furthermore, SF3A2 participated in the regulation of both extrinsic and intrinsic apoptosis, leading to cisplatin resistance in TNBC cells. Collectively, these findings reveal a previously unknown role of SF3A2 in TNBC progression and cisplatin resistance, highlighting SF3A2 as a potential therapeutic target for patients with TNBC.

Contralateral axillary lymph node metastasis in breast cancer: An oligometastatic-like disease.

BACKGROUND: Contralateral axillary lymph node metastasis (CAM) is rare. It remains controversial whether CAM should be regarded as a regional or distant metastatic disease. Our study aims to investigate the accurate clinical orientation and management of CAM. METHODS: Two hundred and ninety-nine female patients diagnosed with breast cancer from 2000 to 2014 and confirmed to develop CAM, oligometastasis (OM) or locoregional recurrence (LRR) at Fudan University Shanghai Cancer Center (FUSCC) were included in this study. Baseline information and survival outcomes were analyzed and compared among the three groups. RESULTS: Patients with CAM exhibited similar overall survival (OS) and progression-free survival (PFS) to those with OM, but worse than those with LRR (HR: 0.47 [95 % CI: 0.27-0.85], p = 0.0097; HR:0.39 [95 % CI: 0.24-0.63], p < 0.0001, respectively). Considering the patients presented with CAM or OM as a whole, we found that local treatment combined with systemic treatment did not provide a superior survival benefit over systemic treatment alone. CONCLUSION: CAM was similar to an oligometastatic-like disease, and patients with these diseases may benefit from systemic treatment. Adding local treatment failed to significantly improve OS.

Prognostic factors and clinical outcomes of breast cancer patients with disease progression during neoadjuvant systemic therapy.

BACKGROUND: Disease progression during neoadjuvant systemic therapy for breast cancer indicates poor prognosis, while predictors of the clinical outcomes of these patients remain unclear. By comparing the clinical outcomes of patients with different patterns of salvage treatment strategies, we try to evaluate the factors predicting distant failure and explore the favourable treatment for them. METHODS: Patients with disease progression during neoadjuvant systemic therapy for stage I-III breast cancer diagnosed between January 1, 2008 and July 31, 2021 in Fudan University Shanghai Cancer Center were enrolled. Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions or the appearance of new breast or nodal lesions. Kaplan-Meier, univariate and multivariate Cox proportional hazard regressions were utilized to compare survival outcomes between different salvage treatment strategies. RESULTS: Among 3775 patients treated with NST, 60 (1.6%) patients encountered disease progression. A significant difference between the outcomes of patients receiving direct surgery and other salvage modalities was found (p = 0.007). Triple-negative breast cancer (p = 0.010) and not receiving direct surgery (p = 0.016) were independently associated with distant disease-free survival on multivariate analysis. CONCLUSIONS: Predictors of distant failure in patients with disease progression include triple-negative breast cancer and not receiving direct surgery. Direct surgery seems to be more favourable than other treatments for patients with disease progression. For inoperable patients, neoadjuvant radiation can increase their operability but not improve their prognosis.