Surreal illustration of melanoma cells with DNA and a researcher observing the glow of MMP-9 markers.

MMP-9: A Game-Changing Indicator in Melanoma Treatment?

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Rhea Morgan in Health & Wellness October 2026 • 4 min read.

"Discover how MMP-9 levels could predict the effectiveness of BRAF inhibitors in melanoma patients, offering new hope for personalized cancer therapy."


Melanoma treatment has undergone a revolution in the last decade, thanks to the introduction of immune checkpoint inhibitors and selective tyrosine kinase inhibitors like BRAF and MEK inhibitors. These advancements have significantly improved progression-free survival (PFS) and overall survival (OS) for many patients. Despite these promising results, a considerable number of patients still develop resistance, highlighting the need for more effective biomarkers to guide treatment decisions.

One area of particular interest is the role of matrix metalloproteinases (MMPs), especially MMP-9, in melanoma progression. MMP-9 promotes melanoma's invasiveness and spread by breaking down the extracellular matrix. Its expression is influenced by multiple molecular pathways, epigenetic events, and aberrant activation of signaling pathways like Ras-Raf-MEK-ERK and PI3K/PTEN/AKT/mTOR. Identifying reliable markers that correlate with treatment response remains a critical challenge.

The study by Salemi et al. (2018) explores the potential of MMP-9 as a predictive marker for response to BRAF inhibitors in melanoma patients with the BRAFV600E mutation. This mutation, the most common alteration observed in melanoma, is associated with MMP-9 overexpression. The researchers investigated whether MMP-9 levels, combined with circulating-free DNA analysis, could provide valuable insights into treatment efficacy and patient outcomes.

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BRAF-Targeted Therapy and Resistance

BRAF inhibitors, including vemurafenib and dabrafenib, improved overall survival compared with chemotherapy and were approved for BRAF-mutated metastatic melanoma. BRAF and MEK inhibitor combinations, including dabrafenib with trametinib, have become standard options for BRAF V600 mutation-positive metastatic melanoma and are also used in earlier disease stages, including adjuvant treatment. Despite this progress, innate and acquired therapeutic resistance remains a significant challenge, and treatment failure due to drug resistance continues to affect many patients.

How Was MMP-9 Evaluated in Melanoma Patients?

Surreal illustration of melanoma cells with DNA and a researcher observing the glow of MMP-9 markers.

The study involved a detailed evaluation of MMP-9 in melanoma cells following treatment with dabrafenib, a BRAF inhibitor. The in vitro findings were then validated using data from 26 melanoma patients. Among these patients, 14 were treated with a BRAF inhibitor alone, while 12 received a combination of BRAF and MEK inhibitors. Researchers used ELISA assays and droplet digital PCR to measure MMP-9 serum levels and circulating-free DNA BRAFV600E mutation, respectively.

Statistical analyses were performed to determine the prognostic significance of MMP-9, progression-free survival (PFS), and overall survival (OS) based on BRAFV600E mutation status and MMP-9 levels. The study aimed to uncover potential correlations that could help predict treatment outcomes and guide clinical decision-making.

  • In vitro Analysis: MMP-9 and pEKR1-2 were statistically down-regulated in melanoma cells after treatment with dabrafenib.
  • Circulating-Free DNA: The BRAFV600E mutation was detected in 11 out of 26 melanoma patients, showing higher levels of MMP-9 compared to those with undetectable BRAFV600E mutation.
  • Survival Rates: Higher levels of MMP-9 and circulating-free DNA BRAFV600E mutation were associated with lower PFS and OS.
  • Therapy Monitoring: MMP-9 significantly decreased at T1 and T2, but not at T-last, for patients with detectable circulating-free DNA BRAFV600E mutation.
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Current Evidence in Advanced Melanoma

A 2024 review of advanced melanoma treatment focuses on immune checkpoint inhibitors and BRAF/MEK inhibitors. It emphasizes that treatment decisions are influenced by BRAF mutation status, tumor burden, performance status, prior therapies, and management of brain disease. In resected stage III/IV melanoma, adjuvant BRAF/MEK inhibitors and anti-PD-1 therapy are described as standard care, although a head-to-head clinical trial comparison is lacking. A 2026 review also reports that most patients develop resistance after several treatment cycles and that approximately 70% succumb to disease progression within five years of treatment.

Why Treatment Outcomes Vary

The National Cancer Institute states that melanoma prognosis and treatment options depend on tumor thickness, tumor location, bleeding or ulceration, lymph-node involvement, the number and location of metastases, blood lactate dehydrogenase levels, BRAF mutations, and age. These factors show why a BRAF-focused treatment strategy cannot be applied identically to every patient. BRAF-targeted therapy also involves oral precision drugs that block mutated BRAF protein, with eligibility and side-effect management remaining practical considerations.

These findings underscore the importance of monitoring MMP-9 levels during melanoma treatment, particularly in patients with the BRAFV600E mutation. The initial decrease in MMP-9 levels suggests an early response to BRAF inhibitors, while the lack of sustained reduction may indicate the development of resistance over time.

What Does This Mean for Melanoma Patients?

In conclusion, the study highlights that high levels of MMP-9 and circulating-free DNA BRAFV600E mutation are associated with poorer progression-free survival (PFS) and overall survival (OS). MMP-9 may serve as a promising indicator of response to BRAF inhibitors when combined with the detection of BRAFV600E mutation. Further research is needed to validate these findings and explore the potential of MMP-9 as a therapeutic target in melanoma.

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The Role of MAPK Pathway Inhibition

A review published in 2015 describes selective inhibition of the mitogen-activated protein kinase pathway through BRAF or MEK inhibition as a key component of treatment for BRAF-mutant metastatic melanoma. The review bases this assessment on evidence from several phase III trials. This positions BRAF and MEK inhibition as important treatment tools, while not establishing that a single biomarker can determine every patient's response.

Expanding Treatment Options

Melanoma treatment options described for 2026 include surgery, immunotherapy, targeted therapy, radiation, and emerging mRNA vaccines. The appropriate approach depends on disease stage, BRAF mutation status, and overall health. A 2026 review likewise describes immune checkpoint inhibitors and molecular targeted therapies as transformative developments and discusses potential future changes in melanoma drug therapy.

Rising Burden and Treatment Progress

The global incidence of metastatic melanoma with BRAF mutations is rising. This disease is characterized by aggressive behavior and poor prognosis, creating a substantial systemic challenge. At the same time, immune checkpoint inhibitors and targeted therapies such as BRAF and MEK inhibitors have significantly enhanced reported patient outcomes.

Treatment in Routine Practice

A US real-world study examined first-line treatment patterns for patients with resected BRAF V600-mutated melanoma. Most patients received adjuvant immunotherapy with nivolumab or pembrolizumab rather than the targeted combination of dabrafenib plus trametinib. The study therefore illustrates that real-world treatment choices may favor immunotherapy over targeted therapy in this patient population.

What the biomarker evidence can-and cannot-show

MMP-9’s connection to melanoma is biologically plausible: it can help break down basement-membrane material, and invasive melanoma cell lines have shown more MMP-9 expression and activity than non-invasive lines. Those observations describe a possible role in invasion, not proof that a blood measurement predicts an individual patient’s outcome.[1] [2]

How blood-marker results compare across melanoma reports

A separate report described elevated serum MMP-9 alongside extensive metastases and reduced survival, but another biomarker review noted that MMP-9 did not correlate with time to progression after therapy. The findings address different outcomes and do not point to a uniformly consistent relationship.[3]

What remains uncertain about MMP-9 in melanoma

  • Would MMP-9 levels track a defined clinical outcome consistently across patient groups, given reports of both higher levels alongside extensive metastases and reduced survival and no difference among melanoma groups?[1] [3]
  • How much confidence should be placed in circulating MMP-9 when reported sensitivity and specificity for tumour-marker use are low?[1]

Terms used in the biomarker evidence

MMPs
Matrix metalloproteinases[1]
TIMP-1
Tissue inhibitor of metalloproteinase 1[4]

Sources

  1. Expression and serum levels of MMP-2 and MMP-9 during human melanoma progression. (pubmed.ncbi.nlm.nih.gov)
  2. Matrix Metalloproteinase-9 (MMP-9) polymorphisms in patients with cutaneous malignant melanoma (pmc.ncbi.nlm.nih.gov)
  3. Melanoma’s New Frontier: Exploring the Latest Advances in Blood-Based Biomarkers for Melanoma (pmc.ncbi.nlm.nih.gov)
  4. Serum markers in early-stage and locally advanced melanoma (pmc.ncbi.nlm.nih.gov)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

Everything You Need To Know

1

What is MMP-9, and why is it important in melanoma?

MMP-9, or matrix metalloproteinase-9, is an enzyme that plays a role in breaking down the extracellular matrix, which is the network of proteins and other molecules that surround cells in tissues. In the context of melanoma, MMP-9 promotes the cancer's ability to invade and spread to other parts of the body. It's significant because its levels can indicate how aggressive the melanoma is and how it might respond to certain treatments. MMP-9 expression can be influenced by multiple molecular pathways, epigenetic events, and aberrant activation of signaling pathways like Ras-Raf-MEK-ERK and PI3K/PTEN/AKT/mTOR, making it a key factor in melanoma progression.

2

What are BRAF inhibitors, and how are they used in melanoma treatment?

BRAF inhibitors are a class of drugs used to treat melanoma patients who have a specific mutation called BRAFV600E. These inhibitors target the BRAF protein, which is part of a signaling pathway that controls cell growth. By inhibiting BRAF, these drugs can slow down or stop the growth of melanoma cells. However, not all patients respond to BRAF inhibitors, and some may develop resistance over time. That is why identifying markers like MMP-9 is so important to gauge treatment effectiveness.

3

How was MMP-9 measured and evaluated in melanoma patients in the study?

The study evaluated MMP-9 levels in melanoma patients by first conducting in vitro analysis, meaning in test tubes using melanoma cells treated with dabrafenib, a BRAF inhibitor. These findings were then validated using data from melanoma patients, some treated with a BRAF inhibitor alone and others with a combination of BRAF and MEK inhibitors. The researchers used methods like ELISA assays and droplet digital PCR to measure MMP-9 serum levels and circulating-free DNA BRAFV600E mutation, respectively. The goal was to find correlations between MMP-9 levels, the presence of the BRAFV600E mutation, and patient outcomes like progression-free survival and overall survival.

4

What does it mean for melanoma patients if they have high levels of MMP-9?

High levels of MMP-9 are associated with poorer progression-free survival (PFS) and overall survival (OS) in melanoma patients, particularly those with the BRAFV600E mutation. This suggests that MMP-9 could be a useful indicator of how well a patient will respond to BRAF inhibitors. Monitoring MMP-9 levels during treatment could help doctors determine whether the treatment is working and whether the patient is developing resistance. If MMP-9 levels do not decrease, it may indicate the need for alternative treatment strategies.

5

What is circulating-free DNA analysis, and how does it relate to MMP-9 in melanoma?

Circulating-free DNA analysis in melanoma involves detecting and analyzing DNA that is released by cancer cells into the bloodstream. In this context, the focus is on detecting the BRAFV600E mutation in the circulating-free DNA. The presence of this mutation in the bloodstream, combined with high MMP-9 levels, is associated with poorer outcomes in melanoma patients. Monitoring circulating-free DNA levels can provide additional insights into treatment response and disease progression, complementing the information obtained from MMP-9 level measurements.

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