Resistance to Immune Checkpoint Blockade (ICB) constitutes the current limiting factor for the optimal implementation of this novel therapy, which otherwise demonstrates durable responses with acceptable toxicity scores. This limitation is exacerbated by a lack of robust biomarkers. In this study, we have dissected the basal TME composition at the gene expression and cellular levels that predict response to Nivolumab and prognosis. BCR, TCR and HLA profiling were employed for further characterization of the molecular variables associated with response. The findings were validated using a single-cell RNA-seq data of metastatic melanoma patients treated with ICB, and by multispectral immunofluorescence. Finally, machine learning was employed to construct a prediction algorithm that was validated across eight metastatic melanoma cohorts treated with ICB. Using this strategy, we have unmasked a major role played by basal intratumoral Plasma cells expressing high levels of IGKC in efficacy. IGKC, differentially expressed in good responders, was also identified within the Top response-related BCR clonotypes, together with IGK variants. These results were validated at gene, cellular and protein levels; CD138+ Plasma-like and Plasma cells were more abundant in good responders and correlated with the same RNA-seq-defined fraction. Finally, we generated a 15-gene prediction model that outperformed the current reference score in eight ICB-treated metastatic melanoma cohorts. The evidenced major contribution of basal intratumoral IGKC and Plasma cells in good response and outcome in ICB in metastatic melanoma is a groundbreaking finding in the field beyond the role of T lymphocytes.

Alterations in BRCA1/2 (BRCA) and other homologous recombination repair (HRR) genes have a negative impact on outcomes in patients with metastatic castration-resistant prostate cancer (mCRPC). Poly(adenosine diphosphate-ribose) polymerase inhibitors, the only treatment demonstrated to improve the prognosis of patients with mCRPC, are also being developed for the treatment of patients with metastatic hormone-sensitive prostate cancer (mHSPC). To fully assess their potential benefit in this setting, it is essential to understand how BRCA and HRR defects may influence the prognosis of conventionally treated patients with low and high disease volume. Eligible mHSPC patients diagnosed between January 2018 and December 2023 underwent paired somatic/germline DNA sequencing. Cases with alterations in one or more HRR genes were classified as BRCA, HRR non-BRCA, non-BRCA or non-HRR. Radiographic progression-free survival, time to castration resistance and overall survival were reported for all subgroups; associations between mutations and outcomes were assessed after controlling for treatment modality and baseline characteristics using inverse probability of treatment weighting models. Of 556 patients, 159 (28.6%) had HRR gene alterations: 69 (12.4%) with BRCA and 90 (16.2%) with HRR non-BRCA mutations. mHSPC was synchronous in 451 patients (81.1%) and was classified as high-volume (CHAARTED criteria) in 306 (55%) patients. Within the HRR subgroup, patients with BRCA mutations had significantly worse outcomes across all endpoints (P < 0.005 for all comparisons). Differences in prognosis by BRCA and HRR status were observed in both low- and high-volume subgroups and were independent of treatment with androgen receptor pathway inhibitors or taxanes. Presence of HRR mutations, particularly BRCA alterations, significantly worsened prognosis, regardless of disease volume or treatment regimen. These findings underscore the importance of integrating tumour biology for accurate risk stratification in mHSPC and the design of new treatment strategies and follow-up.

MicroRNAs (miRNA) expression in colorectal (CR) primary tumours can facilitate a more precise molecular characterization. We identified and validated a miRNA profile associated with clinical and histopathological features that might be useful for patient stratification. In situ hybridization array using paraffin-embedded biopsies of CR primary tumours were used to screen 1436 miRNAs. 17 miRNAs were selected for validation by quantitative reverse transcription polymerase chain reaction (qRT-PCR) (n = 192) and were further correlated with clinical and histopathological data. We demonstrated that miRNAs associated to Colorectal Cancer (CRC) diagnosis age (over 50s and 60s) included miR-1-3p, miR-23b-3p, miR-27b-3p, miR-143-3p, miR-145-5p and miR-193b-5p. miR-23b-3p and miR-24-3p discriminated between Lynch Syndrome and sporadic CRC. miR-10a-5p, miR-20a-5p, miR-642b and Let-7a-5p were associated to stroma abundance. miR-642b and Let-7a-5p were associated with to peritumoral inflammation abundance. miR-1-3p, miR-143-3p and miR-145-5p correlated with mucinous component. miR-326 correlated with tumour location (right or left sided). miR-1-3p associated with tumour grade. miR-20a-5p, miR-193b-5p, miR-320a, miR-326 and miR-642b-3p associated to tumour stage and progression. Remarkably, we also demonstrated that miR-1-3p and miR-326 expression significantly associated with patient overall survival (OS). Hierarchical clustering and bioinformatics analysis indicated that selected miRNAs could re-classify the patients and work cooperatively, modulating common target genes involved in colorectal cancer key signalling pathways. In conclusion, molecular characterization of CR primary tumours based on miRNAs could lead to more accurate patient reclassification and may be useful for efficient patient management.

Bladder cancer (BC) is one of the most common tumors in the world. Cystoscopy and tissue biopsy are the standard methods in screening and early diagnosis of suspicious bladder lesions. However, they are invasive procedures that may cause pain and infectious complications. Considering the limitations of both procedures, and the recurrence and resistance to BC treatment, it is necessary to develop a new non-invasive methodology for early diagnosis and multiple evaluations in patients under follow-up for bladder cancer. In recent years, liquid biopsy has proven to be a very useful diagnostic tool for the detection of tumor biomarkers. This non-invasive technique makes it possible to analyze single tumor components released into the peripheral circulation and to monitor tumor progression. Numerous biomarkers are being studied and interesting clinical applications for these in BC are being presented, with promising results in early diagnosis, detection of microscopic disease, and prediction of recurrence and response to treatment.