Despite the improvement achieved by the introduction of HER2-targeted therapy, up to 25% of early human epidermal growth factor receptor 2-positive (HER2+) breast cancer (BC) patients will relapse. Beyond trastuzumab, other agents approved for early HER2+ BC include the monoclonal antibody pertuzumab, the antibody-drug conjugate (ADC) trastuzumab-emtansine (T-DM1) and the reversible HER2 inhibitor lapatinib. New agents, such as trastuzumab-deruxtecan or tucatinib in combination with capecitabine and trastuzumab, have also shown a significant improvement in the metastatic setting. Other therapeutic strategies to overcome treatment resistance have been explored in HER2+ BC, mainly in HER2+ that also overexpress estrogen receptors (ER+). In ER+ HER2+ patients, target therapies such as phosphoinositide-3-kinase (PI3K) pathway inhibition or cyclin-dependent kinases 4/6 blocking may be effective in controlling downstream of HER2 and many of the cellular pathways associated with resistance to HER2-targeted therapies. Multiple trials have explored these strategies with some promising results, and probably, in the next years conclusive results will succeed. In addition, HER2+ BC is known to be more immunogenic than other BC subgroups, with high variability between tumors. Different immunotherapeutic agents such as HER-2 therapy plus checkpoint inhibitors, or new vaccines approaches have been investigated in this setting, with promising but controversial results obtained to date.

Diabetes is related with increased cancer mortality across multiple cancer types. Its role in lung cancer mortality is still unclear. We aim to determine the prognostic value of fasting plasma glucose (FPG) and diabetes mellitus in patients with locally advanced non-small cell lung cancer (NSCLC) treated with concurrent chemoradiotherapy. One-hundred seventy patients with stage III NSCLC received definitive concurrent chemoradiotherapy from 2010 to 2014. Clinico-pathological data and clinical outcome was retrospectively registered. Fifty-six patients (33%), met criteria for type 2 diabetes mellitus (T2DM) at baseline. The prognostic value of FPG and other clinical variables was assessed. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method and Cox proportional models and log-rank test were used. With a median follow-up of 36 months, median PFS was 8.0 months and median OS was 15.0 months in patients with FPG ≥7 mmol/L compared to 20 months (HR 1.13; 95% CI 1.07–1.19, p < 0.001) and 31 months (HR 1.09; 95% CI 1.04–1.15; p < 0.001) respectively, for patients with FPG < 7 mmol/L. In the multivariate analysis of the entire cohort adjusted by platinum compound and comorbidities, high levels of FPG as a continuous variable (HR 1.14; 95% CI 1.07–1.21; p < 0.001), the presence of comorbidity (HR 1.72; 95% CI 1.12–2.63; p = 0.012), and treatment with carboplatin (HR 1.95; 95% CI 1.26–2.99; p = 0.002) were independent predictors for shorter OS. In additional multivariate models considering non-diabetic patients as a reference group, diabetic patients with poor metabolic control (HbA1c > 8.5%) (HR 4.53; 95% CI 2.21–9.30; p < 0.001) and those receiving insulin (HR 3.22; 95% CI 1.90–5.46 p < 0.001) had significantly independent worse OS. Baseline FPG level is an independent predictor of survival in our cohort of patients with locally advanced NSCLC treated with concurrent chemoradiotherapy. Studies in larger cohorts of patients are warranted to confirm this relevant association.

Oestrogen receptor positive/ human epidermal growth factor receptor positive (ER+/HER2+) breast cancers (BCs) are less responsive to endocrine therapy than ER+/HER2- tumours. Mechanisms underpinning the differential behaviour of ER+HER2+ tumours are poorly characterised. Our aim was to identify biomarkers of response to 2 weeks’ presurgical AI treatment in ER+/HER2+ BCs. All available ER+/HER2+ BC baseline tumours (n=342) in the POETIC trial were gene expression profiled using BC360™ (NanoString) covering intrinsic subtypes and 46 key biological signatures. Early response to AI was assessed by changes in Ki67 expression and residual Ki67 at 2 weeks (Ki67_2wk). Time-To-Recurrence (TTR) was estimated using Kaplan-Meier methods and Cox models adjusted for standard clinicopathological variables. New molecular subgroups (MS) were identified using consensus clustering. HER2-enriched (HER2-E) subtype BCs (44.7% of the total) showed poorer Ki67 response and higher Ki67_2wk (p<0.0001) than non-HER2-E BCs. High expression of ERBB2 expression, homologous recombination deficiency (HRD) and TP53 mutational score were associated with poor response and immune-related signatures with High Ki67_2wk. Five new MS that were associated with differential response to AI were identified. HER2-E had significantly poorer TTR compared to Luminal BCs (HR 2.55, 95% CI 1.14–5.69; p=0.0222). The new MS were independent predictors of TTR, adding significant value beyond intrinsic subtypes. Our results show HER2-E as a standardised biomarker associated with poor response to AI and worse outcome in ER+/HER2+. HRD, TP53 mutational score and immune-tumour tolerance are predictive biomarkers for poor response to AI. Lastly, novel MS identify additional non-HER2-E tumours not responding to AI with an increased risk of relapse. Cancer Research UK (CRUK/07/015).

Purpose: Aromatase inhibitor (AI) treatment is the standard of care for postmenopausal women with primary estrogen receptor–positive breast cancer. The impact of duration of neoadjuvant endocrine therapy (NET) on molecular characteristics is still unknown. We evaluated and compared changes of gene expression profiles under short-term (2-week) versus longer-term neoadjuvant AIs. Experimental Design: Global gene expression profiles from the PeriOperative Endocrine Therapy for Individualised Care (POETIC) trial (137 received 2 weeks of AIs and 47 received no treatment) and targeted gene expression from 80 patients with breast cancer treated with NET for more than 1 month (NeoAI) were assessed. Intrinsic subtyping, module scores covering different cancer pathways and immune-related genes were calculated for pretreated and posttreated tumors. Results: The differences in intrinsic subtypes after NET were comparable between the two cohorts, with most Luminal B (90.0% in the POETIC trial and 76.3% in NeoAI) and 50.0% of HER2 enriched at baseline reclassified as Luminal A or normal-like after NET. Downregulation of proliferative-related pathways was observed after 2 weeks of AIs. However, more changes in genes from cancer-signaling pathways such as MAPK and PI3K/AKT/mTOR and immune response/immune-checkpoint components that were associated with AI-resistant tumors and differential outcome were observed in the NeoAI study. Conclusions: Tumor transcriptional profiles undergo bigger changes in response to longer NET. Changes in HER2-enriched and Luminal B subtypes are similar between the two cohorts, thus AI-sensitive intrinsic subtype tumors associated with good survival might be identified after 2 weeks of AI. The changes of immune-checkpoint component expression in early AI resistance and its impact on survival outcome warrants careful investigation in clinical trials.

Purpose: Elacestrant has shown significantly prolonged progression-free survival compared with standard-of-care endocrine therapy in estrogen receptor–positive (ER-positive), HER2-negative metastatic breast cancer, whereas potential benefit in early-stage disease requires further exploration. The SOLTI-ELIPSE window-of-opportunity trial investigated the biological changes induced by a short course of preoperative elacestrant in postmenopausal women with early breast cancer. Patients and Methods: Eligible patients with untreated T1c (≥1.5 cm)-T3, N0, ER-positive/HER2-negative breast cancer with locally assessed Ki67 ≥10% received elacestrant at a daily dose of 345 mg for 4 weeks. The primary efficacy endpoint was complete cell cycle arrest, defined as Ki67 ≤2.7%, on day 28. Results: Overall, 22 patients were evaluable for the primary endpoint. Elacestrant was associated with a complete cell cycle arrest rate of 27.3% and a statistically significant Ki67 geometric mean change of −52.9% (P = 0.007; 95% confidence interval, −67.4 to −32.1). Notably, the treatment with elacestrant led to a shift toward a more endocrine-sensitive and less proliferative tumor phenotype based on PAM50-based gene signatures. Elacestrant increased the expression of immune-response genes (GZMB, CD4, and CD8A) and suppressed proliferation and estrogen-signaling genes (MKI67, ESR1, and AR). These biological changes were independent of the levels of Ki67 suppression on day 28. The most common adverse events were grade 1 anemia (21.7%), hot flushes (8.7%), constipation (8.7%), and abdominal pain (8.7%). One patient experienced a grade 3 cutaneous rash, leading to treatment discontinuation. No other serious adverse events were reported. Conclusions: Preoperative treatment with elacestrant in early breast cancer demonstrated relevant biological and molecular responses and exhibited a manageable safety profile. These findings support further investigation of elacestrant in the early setting.

Triple-negative breast cancer (TNBC) is a highly aggressive subtype with limited therapeutic options, leading to higher relapse rates and mortality. Identifying prognostic biomarkers like caveolin-1 (CAV1) is crucial for personalized treatment. CAV1 influences tumor progression and chemotherapy response, particularly through its interaction with the tumor microenvironment (TME) and cancer metabolism. Understanding the prognostic value of CAV1 in different cellular compartments is essential for its clinical application in TNBC. In the methods section CAV1 gene expression in TNBC was evaluated using in silico analysis, followed by the immunohistochemical staining of tumor cytoplasm (cCAV1) and stromal cells (sCAV1) in 58 early-stage TNBC patients. Statistical analyses were performed to correlate CAV1 expression with clinicopathological features and survival. In the results section, in silico analysis revealed higher CAV1 expression in TNBC, correlating with shorter overall survival. In the patient samples, cCAV1 was observed in 10.3% of cases, and was associated with larger tumors, higher grades, and poorer prognoses. sCAV1 was detected in 42% of cases, associated with less proliferative and less aggressive tumors, but did not significantly impact prognoses. In conclusion, cCAV1 expression is a significant prognostic marker in early-stage TNBC, highlighting the importance of assessing CAV1 in different cellular compartments. Further research is needed to explore the mechanisms and clinical implications of cCAV1.