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Dr. Babasaheb Ambedkar Technological University, Lonere-Raigad, Maharashtra.
Glioblastoma and melanoma are among the most lethal malignancies in clinical oncology, characterized by aggressive biological behavior, marked intratumoral heterogeneity, and intrinsic or acquired resistance to therapy. Although these tumors originate from distinct cell lineages and arise in divergent anatomical environments, accumulating evidence reveals significant molecular, biological, and clinical convergence between them, offering valuable translational insights. This review provides a critical comparative synthesis of glioblastoma and melanoma subtypes, with a focus on shared oncogenic signaling pathways, tumor heterogeneity, immune evasion strategies, and resistance to current therapeutic modalities. Both malignancies exhibit frequent dysregulation of core signaling cascades, particularly the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathways, alongside recurrent alterations in key regulatory genes such as PTEN, BRAF, and TERT. These overlapping molecular aberrations drive tumor proliferation, invasiveness, metabolic plasticity, and reduced responsiveness to conventional and targeted therapies. However, critical differences in the tumor microenvironment and immune landscape significantly influence therapeutic outcomes. Melanoma is typically highly immunogenic, with elevated tumor mutational burden and robust immune infiltration, accounting for the clinical success of immune checkpoint inhibitors. In contrast, glioblastoma is defined by a profoundly immunosuppressive microenvironment, limited immune cell infiltration, low neoantigen load, and restricted drug penetration due to the blood–brain barrier, collectively limiting immunotherapeutic efficacy. While precision oncology has transformed melanoma management, its impact in glioblastoma remains modest. Nevertheless, emerging evidence supports selective translation of targeted therapies in defined molecular contexts, including BRAF V600E–mutant gliomas. Advances in biomarker discovery, liquid biopsy approaches, and integrative multi-omics technologies further offer opportunities for improved patient stratification and personalized therapeutic strategies
Overview of glioblastoma and melanoma:
Two of the most aggressive and difficult-to-treat cancers in oncology are glioblastoma and melanoma. Both malignancies show significant genomic heterogeneity, fast disease development, and a strong tendency toward therapy resistance while coming from different cellular sources and anatomical locations. While glioblastoma continues to show poor patient outcomes, advances in molecular biology and immuno-oncology have greatly enhanced the knowledge and clinical management of melanoma, highlighting the urgent need for novel and efficient therapeutic approaches [1,2]. As a World Health Organization (WHO) grade IV astrocytoma, glioblastoma (GBM) is the most prevalent and deadly primary malignant tumor of the central nervous system [3]. It is distinguished by significant genetic instability, necrosis, microvascular growth, and widespread cellular infiltration. Key genetic and epigenetic changes, such as telomerase reverse transcriptase (TERT) promoter mutations, phosphatase and tensin homolog (PTEN) loss, isocitrate dehydrogenase (IDH) mutation status, and epidermal growth factor receptor (EGFR) amplification, have been discovered by extensive molecular profiling studies. These findings have improved prognostic stratification and diagnostic classification. [3,4]. Despite these developments, the current standard of care—maximal safe surgical resection followed by radiation with concurrent and adjuvant temozolomide—only slightly improves survival, with median overall survival seldom surpassing 14–18 months [5]. The blood–brain barrier, intratumoral heterogeneity, tumor recurrence, and a highly immunosuppressive tumor microenvironment continue to be significant obstacles to treatment effectiveness [6].
The majority of skin cancer-related deaths worldwide are caused by melanoma, a malignant tumor that develops from melanocytes and is one of the most aggressive types of the disease [2]. Unlike glioblastoma, melanoma has benefited greatly from developments in immunotherapy and molecularly targeted treatments. Selective BRAF and MEK inhibitors have been developed as a result of dysregulation of the mitogen-activated protein kinase (MAPK) signaling system, which is most frequently caused by mutations in BRAF, NRAS, and KIT. This has significantly improved progression-free and overall survival [7,8]. Moreover, immune checkpoint drugs that target cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1) have significantly changed therapeutic paradigms since melanoma is highly immunogenic [9,10]. Tumor biology, immune evasion mechanisms, and variable therapy responsiveness can all be better understood by comparing glioblastoma with melanoma. Due in significant part to its immune-privileged position, limited lymphocyte infiltration, and immunosuppressive tumor microenvironment, glioblastoma has shown little benefit from such techniques, despite melanoma emerging as a model for effective immunotherapy [10]. It is essential to comprehend these basic distinctions in order to find new therapeutic targets and modify effective treatment plans for various tumor types.
From a molecular standpoint, important oncogenic signaling pathways that control invasion, survival, and proliferation power both cancers. While melanoma usually contains mutations in the MAPK pathway, specifically BRAF and NRAS, glioblastoma is often linked to changes in EGFR, PTEN, and TERT [3,7]. Comparative analysis of these pathways sheds light on how different oncogenic drivers affect treatment resistance and responsiveness in various cancer types. Melanoma and glioblastoma are significant examples of opposing paradigms in cancer immunotherapy. Melanoma has become a standard for effective immuno-oncology due to its exceptional and long-lasting responses to immune checkpoint inhibitors that target CTLA-4 and PD-1 [9,10]. Glioblastoma, on the other hand, has not responded well to comparable immunotherapeutic strategies, mostly because of its immunosuppressive tumor microenvironment, limited lymphocyte infiltration, and blood–brain barrier [6]. By comparing these two malignancies, immune evasion mechanisms that could account for divergent treatment results can be identified. Additionally, melanoma is used as a translational model to assess new therapeutic techniques, like as combination regimens and biomarker-driven treatment selection, which could guide future glioblastoma management strategies [2,8].
With an emphasis on comparable oncogenic signaling pathways, tumor heterogeneity, immune evasion mechanisms, and treatment resistance, this study aims to objectively analyze the molecular and clinical similarities between glioblastoma and melanoma subtypes. This review aims to find convergent and divergent characteristics that affect disease progression and treatment efficacy by combining data from genomic profiling, clinical outcomes, and responses to targeted and immunotherapies. Comprehending these parallels and discrepancies could aid in the translation of efficacious therapeutic techniques and promote the creation of innovative, logical treatment methods for aggressive cancers.
2. Molecular Similarities: -
Molecular Similarities between Glioblastoma and Melanoma:
Glioblastoma (GBM) and melanoma originate from different organs, but they have significant molecular and signaling similarities that underpin their aggressive nature, resistance to treatment, and recurrence. Recurrent genetic changes, convergence on important carcinogenic signaling pathways, and common transcriptional and epigenetic regulatory mechanisms are some of these characteristics.
Shared Genetic Alterations:
Both GBM and melanoma typically exhibit changes in oncogenes and tumor suppressor genes. Both cancers frequently result in the loss or inactivation of phosphatase and tensin homolog (PTEN), which leads to the unregulated activation of downstream survival pathways, including the PI3K/AKT axis. In GBM and metastatic melanoma, PTEN loss has been linked to poor clinical outcomes, therapeutic resistance, and enhanced tumor invasiveness [11–13].
While BRAF mutations, notably the V600E variant, are a characteristic molecular marker of melanoma, they are also found in a minority of GBM, particularly in epithelioid GBM subtypes and younger individuals. Tumor growth and survival are encouraged by these alterations, which constitutively activate the MAPK pathway [7,14]. Overlapping molecular vulnerabilities that could be therapeutically exploited are highlighted by the presence of shared oncogenic drivers.
Convergent Oncogenic Signaling Pathways:
Major growth and survival signaling cascades, including the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR and mitogen-activated protein kinase (MAPK) pathways, are dysregulated in both GBM and melanoma. Increased proliferation, metabolic adaptability, angiogenesis, and resistance to apoptosis are all influenced by aberrant activation of these pathways [15,16].
While BRAF or NRAS mutations frequently drive constitutive MAPK signaling in melanoma, upstream receptor tyrosine kinase changes, such as EGFR amplification or mutation, function as dominant activators in GBM. Crucially, both tumors have been shown to exhibit cross-talk between the MAPK and PI3K/AKT pathways, which makes therapeutic targeting more challenging and promotes adaptive resistance mechanisms. [17,18].
Epigenetic and Transcriptional Regulation:
Another common molecular characteristic is epigenetic dysregulation. Widespread changes in DNA methylation patterns, histone modifications, and chromatin remodeling are seen in both GBM and melanoma, and these changes impact tumor plasticity and stem-like characteristics. While melanoma exhibits substantial epigenetic remodeling linked to therapeutic resistance and phenotypic change, GBM's DNA methylation status, especially MGMT promoter methylation, has prognostic and predictive significance [19,20]. GBM and melanoma have some commonality in transcriptional processes linked to stemness, invasion, immunological evasion, and metabolic reprogramming. Interestingly, glial progenitor programs in GBM and neural crest-like transcriptional states found in melanoma suggest convergent evolutionary adaptations that promote tumor aggressiveness [21,22].
3. Tumor Microenvironment & Immunity: -
Tumor Microenvironment and Immune Regulation in Glioblastoma and Melanoma:
In both glioblastoma (GBM) and melanoma, the tumor microenvironment (TME) is critical for tumor growth, immune evasion, and treatment resistance. These cancers have a number of immunosuppressive characteristics, including as immune checkpoint activation, defective antigen presentation, and the recruitment of immunoregulatory stromal and myeloid cells, even though they originate from different organs. Nonetheless, there are significant differences between the two malignancies in the degree and functional effects of immune regulation.
Immune Evasion Mechanisms:
A highly immunosuppressive milieu that restricts efficient antitumor immune responses is a characteristic of glioblastoma. Low tumor mutational burden, decreased neoantigen presentation, and compromised dendritic cell activation are important causes. GBM cells actively release immunosuppressive cytokines including interleukin-10 (IL-10) and transforming growth factor-β (TGF-β), which reduce cytotoxic T-cell activity and stimulate the development of regulatory T-cells (Treg) [6,23]. Furthermore, up to 30–50% of the tumor mass may consist of glioblastoma-associated microglia and macrophages (GAMs), which mostly display an M2-like, tumor-supportive phenotype that promotes angiogenesis, invasion, and immunological tolerance [24].
Melanoma, on the other hand, exhibits a relatively immunogenic TME, which is mostly due to its high mutational burden and abundance of neoantigens produced by UV-induced DNA damage. However, melanoma cells use adaptive immune resistance mechanisms, such as immune checkpoint ligand overexpression, antigen expression loss, and immunosuppressive factor release, to avoid immune destruction [25]. In a subset of patients receiving immunotherapy, these mechanisms restrict long-lasting responses and contribute to the advancement of the disease.
PD-1/PD-L1 and Immune Checkpoint Regulation:
Immune escape in glioblastoma and melanoma is mostly dependent on immune checkpoint mechanisms, including the programmed cell death protein-1 (PD-1)/programmed death-ligand 1 (PD-L1) axis. Tumor cells and infiltrating myeloid cells in GBM tumors often express PD-L1, which causes T-cell fatigue and diminished effector function [26]. The restricted effects of the blood–brain barrier, severe immunosuppression, and restricted T-cell infiltration have all contributed to the moderate clinical responses to PD-1/PD-L1 inhibition in GBM [27].
In contrast, melanoma has become a standard cancer for immunological checkpoint treatment. In advanced melanoma, inhibition of PD-1 and cytotoxic T-lymphocyte–associated antigen-4 (CTLA-4) has produced notable and long-lasting survival advantages [9,28]. Improved responses are linked to tumor-infiltrating lymphocytes (TILs), interferon-γ-driven inflammation, and PD-L1 expression, highlighting the significance of an established antitumor immune response [29].
TME Characteristics and Inflammation:
Melanoma and glioblastoma have quite different TME inflammation. Sparse cytotoxic T-cell infiltration and the predominance of immunosuppressive myeloid populations define GBM's largely non-inflammatory or "cold" immunological profile [24, 27]. Immune dysfunction and treatment resistance are further reinforced by hypoxia, abnormal angiogenesis, and metabolic reprogramming.
Melanoma usually exhibits an inflammatory or "hot" TME that is enhanced with pro-inflammatory cytokines, natural killer cells, and CD8? T cells, all of which promote immunotherapy response [29]. However, immunological depletion and resistance may also be caused by chronic inflammation, underscoring the dynamic nature of immune control in the development of melanoma.
4.Clinical and Histological Subtypes of Glioblastoma and Melanoma: -
Glioblastoma Subtypes:
Both histologically and molecularly, glioblastoma (GBM) is a very diverse cancer. In the past, histological characteristics such cellular atypia, necrosis, and microvascular growth were used to categorize GBM. However, various molecular subgroups that more accurately reflect tumor biology and clinical behavior have been identified as a result of extensive genomic research, especially those from The Cancer Genome Atlas (TCGA).
GBM was first divided into four molecular subtypes by TCGA: Classical, Mesenchymal, Proneural, and Neural.
Melanoma Subtypes:
With several clinical, histological, and molecular subtypes that each show unique patterns of mutation, development, and response to treatment, melanoma is likewise a physiologically varied cancer.
Melanoma is classified clinically and physically as follows:
Mutations in the MAPK signaling pathway, specifically BRAF (V600E) and NRAS mutations, are commonly found in cutaneous melanoma. On the other hand, uveal melanoma is primarily caused by GNAQ and GNA11 mutations rather than BRAF or NRAS, whereas acral and mucosal melanomas have lower UV mutational burden and higher rates of KIT changes [32–34].
Melanoma subgroups that differ in growth pattern, invasion depth, and risk for metastasis include superficial spreading melanoma, nodular melanoma, lentigo maligna melanoma, and acral lentiginous melanoma. Molecular categorization has grown in significance in directing the choice of immunotherapy and targeted therapy [35].
Comparative Features of Glioblastoma and Melanoma Subtypes:
GBM and melanoma share a number of similar biological characteristics despite coming from different organs. Due to a variety of genetic changes and adaptive signaling networks, both show significant intra-tumoral and inter-tumoral variability. Both cancer subtypes exhibit dysregulated cell cycle regulation, PTEN loss, and changes in the PI3K/AKT and MAPK pathways [11].
Clinically, therapy choice and prognosis are directly impacted by subtype classification in both cancers. GBM subtypes have demonstrated limited therapeutic stratification success, highlighting fundamental differences in tumor microenvironment and immune accessibility, whereas melanoma subtypes, especially BRAF-mutant cutaneous melanoma, have benefited greatly from targeted therapies and immune checkpoint inhibitors [6,10]. Therefore, comparing GBM and melanoma subtypes offers a useful paradigm for comprehending how immunological interactions, tissue origin, and molecular background affect resistance mechanisms and therapeutic responsiveness.
5. Therapeutic Strategies in Glioblastoma and Melanoma: -
Standard Treatment Approaches:
The care of glioblastoma (GBM) is still primarily focused on a multimodal approach that includes maximal safe surgical resection, fractionated radiation, and concurrent and adjuvant temozolomide (TMZ), sometimes known as the Stupp protocol [36]. Durable disease management is limited by infiltrative tumor development and early recurrence, even with improved surgical procedures and radiation administration. One of the few confirmed predictive biomarkers that increases sensitivity to alkylating treatment is methylation of the O6-methylguanine-DNA methyltransferase (MGMT) promoter [37].
On the other hand, over the past ten years, there has been a paradigm shift in the treatment of melanoma. Surgical excision is the main treatment for early-stage melanoma, whereas systemic treatments, such as immune checkpoint inhibitors and targeted medicines, are becoming more and more important for advanced disease [38]. In individuals with high-risk melanoma, adjuvant and neoadjuvant immunotherapy have dramatically decreased recurrence rates [39].
Targeted Therapy and Resistance Mechanisms:
In GBM, targeted therapy has had mixed results. Clinical studies of EGFR inhibitors and other targeted medicines have mainly failed to increase overall survival, despite regular changes in EGFR, PTEN, and PI3K/AKT/mTOR pathways providing good biological rationale [1]. Intratumoral heterogeneity, activation of adaptive signaling pathways, and limited medication penetration via the blood–brain barrier is contributing factors [40].
In contrast, melanoma has benefited greatly from molecular targeting of the MAPK pathway, especially in tumors with BRAF V600 mutations. When compared to monotherapy, combined BRAF and MEK inhibition dramatically increases response rates and progression-free survival [8]. However, additional mutations, route reactivation, and phenotypic flipping frequently result in acquired resistance, which eventually causes the disease to worsen [41].
Immunotherapy Outcomes and Limitations:
The treatment of melanoma has been transformed by immunotherapy. Immune checkpoint drugs that target PD-1 (nivolumab, pembrolizumab) and CTLA-4 (ipilimumab) have shown long-term survival advantages and persistent responses, with a subset of patients experiencing functional cure [9,28]. Combination immunotherapy increases efficacy even more, albeit at the expense of more immune-related side effects [42]. On the other hand, immune checkpoint inhibition has not demonstrated much clinical effect for GBM. Anti-PD-1 and anti-CTLA-4 antibodies have not been shown to significantly improve survival results in several trials [43]. GBM's immunosuppressive tumor microenvironment, low tumor mutational burden, lack of tumor-infiltrating lymphocytes, and systemic lymphopenia brought on by conventional therapies are the reasons for its limited efficacy [44]. Vaccines, oncolytic viruses, CAR-T cells, and combination immunotherapy are examples of emerging approaches that are being actively studied but are still at the experimental stage [45].
6. Future Directions: Converging Therapeutic and Translational Opportunities in Glioblastoma and Melanoma
Cross-application of Therapeutic Strategies
Glioblastoma and melanoma possess common oncogenic signaling networks despite having different tissue origins, which supports the idea that treatment approaches can be applied to both conditions. Particularly in pediatric and young adult populations, targeted inhibition of the MAPK pathway, especially with BRAF and MEK inhibitors, has shown significant efficacy in BRAF-mutant melanoma and has showed promise in a subgroup of BRAF V600E-mutant gliomas [8,46]. Similar to this, a common therapeutic possibility is the manipulation of the PI3K/AKT/mTOR pathway, which is often changed in both cancers by PTEN loss or upstream receptor tyrosine kinase activation [11]. Clinical trial design for glioblastoma is increasingly influenced by lessons learned from combination therapies in melanoma, such as dual MAPK blockade or targeted therapy paired with immunotherapy, however obstacles unique to the central nervous system still exist [6].
Shared Biomarkers and Predictive Indicators:
For translational oncology to advance across both malignancies, shared molecular and immunological biomarkers must be found. Melanoma and glioblastoma frequently exhibit changes in BRAF, PTEN, and TERT promoter alterations, which have consequences for prognosis and treatment [7,47]. Furthermore, immune-related indicators like T-cell infiltration patterns, tumor mutational burden (TMB), and PD-L1 expression have been identified as predictors of response to immune checkpoint inhibitors in melanoma and are currently being studied in glioblastoma [2,48]. Exosomal RNA signatures and circulating tumor DNA (ctDNA) are two examples of circulating biomarkers that provide non-invasive methods for tracking disease progression and evaluating therapy response in both types of tumors [49]. It is still crucial to standardize and validate these biomarkers in various tumor situations.
Role of Personalized and Precision Medicine:
It is anticipated that personalized medicine will revolutionize the treatment of melanoma and glioblastoma in the future. Significant intra-tumoral heterogeneity has been observed in both cancers thanks to developments in next-generation sequencing, single-cell transcriptomics, and spatial profiling, highlighting the drawbacks of standardized treatment methods [50]. While genotype-driven therapy selection for melanoma has already been made possible by molecular stratification, precision medicine techniques are currently being developed for glioblastoma because of the tumor's intricacy and adaptive resistance mechanisms [51]. More efficient, customized treatment approaches for both cancers may be made possible by combining genomic profiling with patient-specific clinical, immunological, and radiographic data—supported by artificial intelligence and machine learning methods [52].
CONCLUSION
Despite originating from distinct cellular lineages and anatomical compartments, glioblastoma and melanoma exhibit convergent molecular, biological, and clinical characteristics that contribute to their aggressive behavior and therapeutic resistance. Both malignancies are marked by pronounced intra- and inter-tumoral heterogeneity, recurrent dysregulation of key oncogenic signaling pathways—including MAPK and PI3K/AKT/mTOR—and frequent alterations in central regulatory genes such as PTEN, BRAF, and TERT. These shared molecular features collectively drive uncontrolled proliferation, invasive growth, metabolic adaptation, and resistance to standard and targeted treatment strategies. Notwithstanding these similarities, fundamental differences in tumor microenvironment and immune architecture critically determine therapeutic responsiveness. Melanoma represents a prototypical immunogenic tumor, in which high tumor mutational burden and robust immune infiltration underpin the clinical efficacy of immune checkpoint inhibition and combination immunotherapies. In contrast, glioblastoma demonstrates limited responsiveness to comparable approaches, largely due to its immunosuppressive microenvironment, low neoantigen burden, restricted lymphocyte infiltration, and the additional constraints imposed by the blood–brain barrier. These observations emphasize the importance of tissue-specific biological and immunological contexts in shaping treatment outcomes and limiting the direct translatability of therapeutic strategies.
Analysis of molecular and clinical subtypes further highlights the differential impact of precision oncology in these diseases. While biomarker-driven stratification has substantially improved therapeutic outcomes in melanoma, its clinical utility in glioblastoma remains limited. Nevertheless, emerging data support selective cross-application of targeted therapies in defined molecular subsets, particularly in BRAF V600E–mutant gliomas. Concurrent advances in biomarker discovery, liquid biopsy methodologies, and integrative multi-omics profiling offer opportunities to enhance patient stratification, disease monitoring, and therapeutic decision-making across both tumor types. In conclusion, comparative evaluation of glioblastoma and melanoma provides valuable insights into shared oncogenic mechanisms and context-dependent therapeutic vulnerabilities. Leveraging translational lessons from melanoma may inform the development of rational combination strategies, biomarker-guided clinical trials, and individualized treatment approaches in glioblastoma. Continued progress will depend on the integration of comprehensive molecular profiling, modulation of the tumor microenvironment, and innovative therapeutic platforms aimed at overcoming resistance and improving clinical outcomes in these highly aggressive malignancies.
REFERENCES
Nikhil Patil, Chetan Girase, Ankita Chaudhari, Bhagyashri Patil, Akshata Girase, Purushottam Patil, Sujata Girase, Himadri Patil, Bhupendra Mahale, Molecular and Clinical Parallels between Glioblastoma and Melanoma Subtypes: A Comparative Review, Int. J. of Pharm. Sci., 2026, Vol 4, Issue 5, 7672-7687, https://doi.org/10.5281/zenodo.20426980
10.5281/zenodo.20426980