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Cutaneous melanoma is a highly aggressive skin cancer prone to relapse and metastasis. Surgery is often curative when combined with early screening and prevention. However, in recurrent or advanced disease, the development of new targeted and immune therapies has demonstrated promising clinical outcomes, although the acquisition of resistance limits their effectiveness. Thus, new therapeutic approaches are needed. Emerging data indicate that the Hedgehog (Hh) pathway, which is essential for embryonic development, is aberrantly reactivated in melanoma and may represent a promising therapeutic target. Here, we demonstrate its chronic up-modulation in a panel of patient-derived cell lines and, by investigating the underlying molecular mechanisms, we excluded mutations in the principal components of the pathway. We observed reduced PTCH1 and SUFU repressors expression and GLI2 upregulation as common melanoma features. At the same time, copious SHH release, the principal PTCH1 ligand, evidenced autocrine Hh signaling activation. Consistently, a tendency of greater level of this factor resulted higher in the blood of patients compared to controls, confirming the relevance of ligand-dependent trigger in melanoma. The therapeutic potential of inhibiting the Hh pathway is highlighted by the reduced proliferation and migration observed in the presence of clinically approved pharmacological Hh antagonists. Profiling inflammatory mediators revealed significant modulation upon treatment with SMO inhibitors, possibly affecting chemotactic and immune functions. Collectively, these findings provide deeper insight into the role of the Hh pathway in melanoma and support the potential repurposing of Hh inhibitors as therapeutic agents for melanoma.

Background As crucial regulators of the immune response against pathogens, macrophages have been extensively shown also to be important players in several diseases, including cancer. Specifically, breast cancer macrophages tightly control the angiogenic switch and progression to malignancy. ID4, a member of the ID (inhibitors of differentiation) family of proteins, is associated with a stem-like phenotype and poor prognosis in basal-like breast cancer. Moreover, ID4 favours angiogenesis by enhancing the expression of pro-angiogenic cytokines interleukin-8, CXCL1 and vascular endothelial growth factor. In the present study, we investigated whether ID4 protein exerts its pro-angiogenic function while also modulating the activity of tumour-associated macrophages in breast cancer. Methods We performed IHC analysis of ID4 protein and macrophage marker CD68 in a triple-negative breast cancer series. Next, we used cell migration assays to evaluate the effect of ID4 expression modulation in breast cancer cells on the motility of co-cultured macrophages. The analysis of breast cancer gene expression data repositories allowed us to evaluate the ability of ID4 to predict survival in subsets of tumours showing high or low macrophage infiltration. By culturing macrophages in conditioned media obtained from breast cancer cells in which ID4 expression was modulated by overexpression or depletion, we identified changes in the expression of ID4-dependent angiogenesis-related transcripts and microRNAs (miRNAs, miRs) in macrophages by RT-qPCR. Results We determined that ID4 and macrophage marker CD68 protein expression were significantly associated in a series of triple-negative breast tumours. Interestingly, ID4 messenger RNA (mRNA) levels robustly predicted survival, specifically in the subset of tumours showing high macrophage infiltration. In vitro and in vivo migration assays demonstrated that expression of ID4 in breast cancer cells stimulates macrophage motility. At the molecular level, ID4 protein expression in breast cancer cells controls, through paracrine signalling, the activation of an angiogenic programme in macrophages. This programme includes both the increase of angiogenesis-related mRNAs and the decrease of members of the anti-angiogenic miR-15b/107 group. Intriguingly, these miRNAs control the expression of the cytokine granulin, whose enhanced expression in macrophages confers increased angiogenic potential. Conclusions These results uncover a key role for ID4 in dictating the behaviour of tumour-associated macrophages in breast cancer.

Basal cell carcinoma (BCC) is the most common skin cancer, predominantly affecting sun-exposed areas. It typically grows slowly and rarely metastasizes, though untreated cases can cause significant tissue destruction and morbidity. Its pathogenesis primarily involves dysregulation of the Hedgehog (HH) signaling pathway, mainly through mutations in PTCH1 or SMO genes, leading to chronic activation of downstream GLI transcription factors. Accordingly, current targeted therapies for locally advanced, unresectable, or metastatic BCC focus on SMO inhibition, using orally administered drugs such as vismodegib and sonidegib. Although these therapies have shown success, many patients develop resistance, with about 50% harboring mutated SMO. In numerous cases, genetic determinants (sometimes pre-existing) of resistance remain unidentified, complicating patient management. Here, we report a case of a 58-year-old female with advanced BCC who initially exhibited a favorable response to sonidegib but developed resistance after approximately one year. This resistance was not attributable to the acquired mutations in SMO but rather to intra-tumor heterogeneity and additional mutations in critical driver genes, including TP53, APC, FGFR1 and NOTCH1, which likely enable HH pathway inhibition. To our knowledge, this is the first report documenting a sonidegib resistance mechanism in BCC that is independent of HH pathway mutations. This case highlights the complexity of resistance mechanisms to HH inhibitors and underscores the critical need for comprehensive molecular tumor profiling prior to initiating targeted therapy.

Background Bcl-xL plays an important role in tumors from different origins, including melanoma, and for this reason it has been widely targeted with small-molecule BH3 mimetics, which unfortunately show several adverse effects. To overcome this limitation, selective Bcl-xL proteolysis-targeting chimera degraders have been developed. Among these, DT2216, a candidate in phase I/II clinical trials, has demonstrated antitumoral activity in preclinical cancer models from different origins, not including melanoma. Methods By using several established and patient-derived BRAF wild type and mutated melanoma cells, we performed western blot analysis and MTT assay to study DT2216 effect on Bcl-xL protein levels and cell viability, respectively. Combination studies were performed on BRAF mutated melanoma cells treated with DT2216 and Dabrafenib/Trametinib or on wild type melanoma cells treated with DT2216 and Trametinib or S63845. Combination index was calculated to study drug interactions. Apoptotic induction was studied through western blot (PARP-1 cleavage), cytofluorimetric (subG1 peak in the cell cycle) and live-cell fluorescent imaging of activated caspases 3/7 analyses. Group differences were analysed with a two-sided paired or unpaired Student’s t-test. To investigate the effect of the combination treatment in vivo, A375luc melanoma cells were inoculated in xenograft mice, then treated with Dabrafenib/Trametinib or DT2216, alone or in combination, for three weeks. Differences between groups, were analysed with Mann-Whitney test. Results DT2216 induced the specific and long-lasting degradation of Bcl-xL protein, and reduced cell viability, in a concentration-dependent manner. Of note, a positive correlation between Bcl-xL degradation and sensitivity to DT2216 was observed, being cells with higher degradation the most sensitive to DT2216. In combination studies, DT2216 was able to enhance the activity of target therapy regardless BRAF mutational status. Moreover, the Mcl-1 specific inhibitor, S63845, potentiated the efficacy of DT2216 in melanoma cells in which DT2216 determined an increase of Mcl-1 protein. Interestingly, DT2216 also increased the activity of target therapy in melanoma cells resistant to Dabrafenib and Trametinib. Finally, experiments in a xenograft mouse melanoma model highlighted DT2216 potentiating effect of target therapy, not only inducing a significant reduction of tumor growth, but also showing a longer disease control. Conclusion Our findings provide new insights for combination therapy including Bcl-xL degradation for melanoma treatment.

Melanoma is a neoplasm with a heterogeneous clinical presentation and several histopathological variants have been described. Although histopathological evaluation remains the diagnostic gold standard, unusual morphology of some melanomas can lead to erroneous pathologic misinterpretation, as they can be confused with other non-melanocytic tumors. Here, we present a case of nodular melanoma with pseudovascular morphology characterized by uncommon empty branching slit-like spaces, reminiscent of rete testis vessels, for which we suggest the name of retiform melanoma to distinguish it from angiomatoid melanoma. Immunohistochemical analysis and ancillary molecular tests helped us characterize this neoplasm, underscoring the need for clinical-morphological-molecular correlation for the correct diagnosis of unusual cases.

Background Unlike many other solid tumors, melanoma cells possess a remarkable ability to dynamically transition between distinct transcriptional states in response to environmental cues or therapeutic pressure. Among the adaptive mechanisms underlying this plasticity, the epithelial-to-mesenchymal transition (EMT) has garnered increasing attention, as it facilitates the shift from a proliferative, epithelial-like phenotype to a more invasive, mesenchymal-like phenotype frequently associated with cellular dormancy, quiescence and resistance to therapy. Despite growing interest in this phenomenon, the characterization of dormant cellular phenotypes and their clinical significance remains incomplete. Methods In this study, we adopted a comprehensive approach integrating patient-derived melanoma cell lines, bulk RNA sequencing from tumor biopsies and analysis of independent bulk and single-cell public datasets. This multi-dimensional strategy enabled the identification of a reproducible dichotomy between “proliferative” and “dormant” phenotypes, characterized by distinct levels of mitotic activity and mesenchymal gene expression profiles. By leveraging an eight-gene transcriptional signature, we constructed a “dormancy score” able to stratify tumors along a dormancy–proliferation axis, revealing strong associations with clinical outcomes such as progression-free survival (PFS), overall survival (OS) and response to immunotherapy. Results Within the dormant-associated gene module, the surface glycoprotein TACSTD2 (TROP2) emerged as a central hub gene. TROP2 expression was consistently upregulated in the dormant-like transcriptional state. Supporting these findings, single-cell RNA sequencing data confirmed that TROP2 marks a rare subpopulation of malignant cells that may constitute a quiescent, therapy-resistant niche. Besides, results highlight a predominant intracellular expression of TROP2 in the dormant phenotype. Conclusions Together, these findings define a robust dormant phenotype in melanoma with both molecular and clinical significance and evaluate TROP2 as a potential biomarker and therapeutic target for identifying and eradicating dormant and treatment-refractory tumor cells.

Background Molecular Tumor Boards (MTB) operating in real-world have generated limited consensus on good practices for accrual, actionable alteration mapping, and outcome metrics. These topics are addressed herein in 124 MTB patients, all real-world accrued at progression, and lacking approved therapy options. Methods Actionable genomic alterations identified by tumor DNA (tDNA) and circulating tumor DNA (ctDNA) profiling were mapped by customized OncoKB criteria to reflect diagnostic/therapeutic indications as approved in Europe. Alterations were considered non-SoC when mapped at either OncoKB level 3, regardless of tDNA/ctDNA origin, or at OncoKB levels 1/2, provided they were undetectable in matched tDNA, and had not been exploited in previous therapy lines. Results Altogether, actionable alterations were detected in 54/124 (43.5%) MTB patients, but only in 39 cases (31%) were these alterations (25 from tDNA, 14 from ctDNA) actionable/unexploited, e.g. they had not resulted in the assignment of pre-MTB treatments. Interestingly, actionable and actionable/unexploited alterations both decreased (37.5% and 22.7% respectively) in a subset of 88 MTB patients profiled by tDNA-only, but increased considerably (77.7% and 66.7%) in 18 distinct patients undergoing combined tDNA/ctDNA testing, approaching the potential treatment opportunities (76.9%) in 147 treatment-naïve patients undergoing routine tDNA profiling for the first time. Non-SoC therapy was MTB-recommended to all 39 patients with actionable/unexploited alterations, but only 22 (56%) accessed the applicable drug, mainly due to clinical deterioration, lengthy drug-gathering procedures, and geographical distance from recruiting clinical trials. Partial response and stable disease were recorded in 8 and 7 of 19 evaluable patients, respectively. The time to progression (TTP) ratio (MTB-recommended treatment vs last pre-MTB treatment) exceeded the conventional Von Hoff 1.3 cut-off in 9/19 cases, high absolute TTP and Von Hoff values coinciding in 3 cases. Retrospectively, 8 patients receiving post-MTB treatment(s) as per physician’s choice were noted to have a much longer overall survival from MTB accrual than 11 patients who had received no further treatment (35.09 vs 6.67 months, p = 0.006). Conclusions MTB-recommended/non-SoC treatments are effective, including those assigned by ctDNA-only alterations. However, real-world MTBs may inadvertently recruit patients electively susceptible to diverse and/or multiple treatments.

Background Circulating tumor DNA (ctDNA) and miRNA (ctmiRNA) are promising biomarkers for early tumor diagnosis, prognosis and monitoring, and to predict therapeutic response. However, a clear understanding of the fine control on their circulating levels is still lacking. Methods Three human colorectal carcinoma cell lines were grown in culture and as tumor xenograft models in nude mice. Chip-based and droplet digital PCR platforms were used to systematically and quantitatively assess the levels of DNAs and miRNAs released into the culture supernatants and mouse blood plasma. Results Strikingly, mutated DNAs from the same (KRAS) and different (PIK3CA and FBWX7) genomic loci were differentially detected in culture supernatants and blood, with LS174T releasing 25 to 60 times less DNA in culture, but giving rise to 7 to 8 times more DNA in blood than LoVo cells. Greater LS174T ctDNA accumulation occurred in spite of similar CD31 immunostaining (micro-vascularization) and lesser proliferation and tissue necrosis as compared to LoVo. As to the three selected miRNAs (miR-221, miR-222 and miR-141), all of them were constitutively present in the plasma of tumor-free mice. Micro-RNA miR-141 was released into HT-29 cell supernatants 10 and 6.5 times less abundantly with respect to LoVo and LS174T, respectively; on the contrary, release of miR-141 in blood of HT-29 xenografted mice was found similar to that observed in LoVo and LS174T mice. Conclusions Taken together, our results support the existence of multiple, finely tuned (non-housekeeping) control gateways that selectively regulate the release/accumulation of distinct ctDNA and miRNA species in culture and tumor xenograft models. Different xenografts (proxies of different patients) considerably differ in gateway usage, adding several layers of complexity to the well-known idea of molecular heterogeneity. We predict that even high tissue representation of mutated DNA and miRNA may result in insufficient diagnostic analyte representation in blood. In this respect, our data show that careful modeling in mice may considerably help to alleviate complexity, for instance by pre-screening for the most abundant circulating analytes in enlarged sets of tumor xenografts.

Background: Approximately 25.0% of metastatic prostate cancer patients harbour DNA damage repair mutations, including BRCA1 and BRCA2, which are actionable targets for poly(ADP-ribose) polymerase (PARP) inhibitors. Accurate detection of BRCA1/2 mutations is critical for guiding targeted therapies, but crucial pre-analytical factors, such as tissue storage duration and DNA fragmentation, drastically affect the reliability of next-generation sequencing (NGS) using real-world diagnostic specimens. Methods: This multicentre study analysed 954 formalin-fixed paraffin-embedded tissue samples from 11 centres, including 559 biopsies and 395 surgical specimens. This study examined the impact of storage duration (<1 year, 1–2 years, and >2 years) and DNA parameters (concentration and fragmentation index) on NGS success rates. Logistic regression and Cox regression analyses were used to assess correlations between these factors and sequencing outcomes. Results: NGS success rates decreased significantly with longer storage, from 87.8% (<1 year) to 69.1% (>2 years). Samples with higher DNA concentrations and fragmentation indexes had higher success rates (p < 0.001). Surgical specimens had superior success rates (83.3%) compared with biopsies (72.8%) due to better DNA quality. The DNA degradation rate was more pronounced in older samples, underscoring the negative impact of extended storage. Conclusions: Timely testing of BRCA1/2 mutations is critical for optimizing the identification of prostate cancer patients eligible for PARP inhibitors. Surgical specimens provide more reliable results than biopsies and minimizing the storage duration significantly enhances testing outcomes. Standardizing pre-analytical and laboratory procedures across centres is essential to ensure personalized treatments and improve patient outcomes.

The circadian system is composed of a set of clock-genes including PERIOD, CLOCK, BMAL1 and CRY . Disrupting this system promotes cancer development and progression. The expression levels of miR-206, miR-219, miR-192, miR-194 and miR-132 regulating clock-genes and three functional polymorphisms rs11133373 C/G, rs1801260 T/C, rs11133391 T/C in CLOCK sequence were associated with the survival of 83 mCRC patients (50 males and 33 females). Longer overall survival (OS) was observed in women compared to men, 50 versus 31 months. This difference was associated with rs11133373 C/C genotype (p = 0.01), rs1801260 T/C+C/C genotype (p = 0.06) and rs11133391 T/T genotype (p = 0.06). Moreover women expressing high levels (H) of miR-192 (p = 0.03), miR-206 (p = 0.003), miR-194 (p = 0.02) and miR-219 (p = 0.002) had a longer OS compared to men. In women longer OS was reinforced by the simultaneous presence of two or more H-miR, 58 months versus 15 months (p = 0.0008); in this group of women an OS of 87 months was reached with the additional presence of rs11133391T/T genotype (p = 0.02). In this study we identified a subgroup of female patients who seems to have a better prognosis. Personalized medicine should prospectively take into account both genetic and gender differences.