Invasive Melanoma Research Articles

RNA-seq validation of microRNA expression signatures for precision melanoma diagnosis and prognostic stratification

BackgroundNew diagnostic tools are needed to improve the diagnosis and risk stratification of cutaneous melanoma. Disease-specific microRNA signatures have been previously described via NanoString profiling of solid biopsy tissue and plasma. This study validated these signatures via next-generation sequencing technology and compared their performance against clinical metrics and other published melanoma signatures.MethodsRNA from 64 plasma and 60 FFPE biopsy samples from individuals with invasive melanoma or related benign/control phenotypes was extracted and enriched for microRNA. RNA sequencing was performed to compute MEL38/MEL12 signature scores. The results were evaluated with published NanoString and RNA sequencing datasets, comprising 548 solid tissue samples and 217 plasma samples, to predict disease status and patient outcome.ResultsThe MEL38 diagnostic signature classifies patients into discrete diagnostic groups via RNA sequencing in either solid tissue or plasma (P < 0.001). In solid tissue, the prognostic MEL12 signature stratifies patients into low-, intermediate- and high-risk groups, independent of clinical covariates. The hazard ratios for 10-year overall survival, based on observed survival intervals, were 2.2 (MEL12 high-risk vs low-risk, P < 0.001) and 1.8 (intermediate-risk vs low-risk, P < 0.001), outperforming other published prognostic models. MEL12 also exhibited prognostic significance in the plasma of 42 patients with invasive disease.ConclusionsThe MEL38 and MEL12 signatures can be assessed in either solid tissue or plasma using RNA-seq and are strong predictors of disease state and patient outcome. Compared with other genomic methods, MEL12 was shown to be the strongest predictor of poor prognosis. MicroRNA expression profiling offers objective, accurate genomic information about a patient’s likelihood of invasive melanoma and prognosis.

An attractor state zone precedes neural crest fate in melanoma initiation.

The field cancerization theory suggests that a group of cells containing oncogenic mutations are predisposed to transformation 1, 2 . We previously identified single cells in BRAF V600E ;p53 -/- zebrafish that reactivate an embryonic neural crest state before initiating melanoma 3-5 . Here we show that single cells reactivate the neural crest fate from within large fields of adjacent abnormal melanocytes, which we term the "cancer precursor zone." These cancer precursor zone melanocytes have an aberrant morphology, dysplastic nuclei, and altered gene expression. Using single cell RNA-seq and ATAC-seq, we defined a distinct transcriptional cell attractor state for cancer precursor zones and validated the stage-specific gene expression initiation signatures in human melanoma. We identify the cancer precursor zone driver, ID1, which binds to TCF12 and inhibits downstream targets important for the maintenance of melanocyte morphology and cell cycle control. Examination of patient samples revealed precursor melanocytes expressing ID1, often surrounding invasive melanoma, indicating a role for ID1 in early melanomagenesis. This work reveals a surprising field effect of melanoma initiation in vivo in which tumors arise from within a zone of morphologically distinct, but clinically covert, precursors with altered transcriptional fate. Our studies identify novel targets that could improve early diagnosis and prevention of melanoma.

Declining invasive and rising insitu melanoma incidence trends in Iceland: A nationwide cohort study.

Melanoma is increasing worldwide, with incidence rates of invasive melanoma and melanoma insitu (MIS) varying by country. To provide updated invasive melanoma and MIS incidence and mortality trends in Iceland and explore differences among sex and rurality. In this whole-population study using the Icelandic Cancer Registry, patients diagnosed with invasive melanoma or MIS between 1957 and 2021 were included. Sex-specific world standardized incidence (WSR) and mortality rates were assessed by rurality. Joinpoint analysis was used to calculate trends using annual per cent change (APC). Invasive melanoma incidence rates increased from 0.66 to 7.0 (men) and 1.6 to 11.0 (women) per 100,000 person-years, and from 0.2 to 4.0 and 0.9 to 9.5 per 100,000 person-years for MIS in men and women, respectively, with a statistically significant linear trend (p = 0.001). WSR peaked in both men and women (10.7, 17.9 per 100,000 person-years) between 2002 and 2006 and has since been trending down. Between 1991 and 2005, the rise in invasive melanoma occurred more frequently in urban regions. Between 2003 and 2005, joinpoint analysis demonstrated a downtrend in invasive melanoma in men and women (-0.29, -0.73; p < 0.05). For MIS, the WSR peaked at 12.4 per 100,000 person-years in women between 1997 and 2001 before down-trending to 4.2. In recent years (2017-2021), the WSR has been steadily increasing in women with an APC of 1.43. Melanoma-specific mortality has decreased since 2012 (-0.07; p < 0.05). Declining invasive melanoma incidence and mortality rates in conjunction with the recent rise in MIS may reflect the impact of Iceland's sun safety and anti-sunbed educational campaigns, federal regulation of sunbeds and earlier melanoma detection in urban areas.

Immunohistochemistry-Assisted Mohs Surgery for Invasive Eyelid and Periorbital Cutaneous Melanoma.

Prior studies describe wide local excision and "slow Mohs" outcomes for periocular melanoma. Mohs micrographic surgery (MMS) with immunohistochemistry maximizes tissue preservation and offers same-day comprehensive margin evaluation, which facilitates expedited repair, and coordination of oculoplastic reconstruction when necessary. To describe oncologic and reconstructive outcomes of invasive periocular cutaneous melanoma treated with immunohistochemistry-assisted MMS. Invasive melanoma cases affecting the eyelids or periorbital region treated with MMS between 2008 and 2018 were reviewed. Eyelid tumors and those in adjacent subunits were compared. Main outcome measures were recurrence, melanoma-specific death, and postreconstructive complications. Of 42 cases, 28 were classified as periorbital and 14 as eyelid involving. Most were T1 (37, 88.1%). There was 1 local recurrence in a patient with persistent positive conjunctival margin (2.4%). No local recurrences were observed in cases where negative Mohs margins were achieved, and no melanoma-related deaths occurred. Eyelid tumors were more likely to result in lid margin involving defects and require oculoplastic reconstruction. Eyelid complications developed in 10 cases (23.8%), and 5 (11.9%) required revision surgery. Mohs micrographic surgery for periocular melanoma results in low rates of local recurrence and melanoma-specific death. Initial tumor location can aid in reconstructive planning.

Tubulin-Targeted Therapy in Melanoma Increases the Cell Migration Potential by Activation of the Actomyosin Cytoskeleton─An In Vitro Study.

One of the most dangerous aspects of cancers is their ability to metastasize, which is the leading cause of death. Hence, it holds significance to develop therapies targeting the eradication of cancer cells in parallel, inhibiting metastases in cells surviving the applied therapy. Here, we focused on two melanoma cell lines─WM35 and WM266-4─representing the less and more invasive melanomas. We investigated the mechanisms of cellular processes regulating the activation of actomyosin as an effect of colchicine treatment. Additionally, we investigated the biophysical aspects of supplement therapy using Rho-associated protein kinase (ROCK) inhibitor (Y-27632) and myosin II inhibitor ((-)-blebbistatin), focusing on the microtubules and actin filaments. We analyzed their effect on the proliferation, migration, and invasiveness of melanoma cells, supported by studies on cytoskeletal architecture using confocal fluorescence microscopy and nanomechanics using atomic force microscopy (AFM) and microconstriction channels. Our results showed that colchicine inhibits the migration of most melanoma cells, while for a small cell population, it paradoxically increases their migration and invasiveness. These changes are also accompanied by the formation of stress fibers, compensating for the loss of microtubules. Simultaneous administration of selected agents led to the inhibition of this compensatory effect. Collectively, our results highlighted that colchicine led to actomyosin activation and increased the level of cancer cell invasiveness. We emphasized that a cellular pathway of Rho-ROCK-dependent actomyosin contraction is responsible for the increased invasive potential of melanoma cells in tubulin-targeted therapy.

Secreted Apoe rewires melanoma cell state vulnerability to ferroptosis.

A major therapeutic barrier in melanoma is the coexistence of diverse cellular states marked by distinct metabolic traits. Transitioning from a proliferative to an invasive melanoma phenotype is coupled with increased ferroptosis vulnerability. However, the regulatory circuits controlling ferroptosis susceptibility across melanoma cell states are unknown. In this work, we identified Apolipoprotein E (APOE) as the top lipid-metabolism gene segregating the melanoma MITFhigh/AXLlow proliferative/ferroptosis-resistant from MITFlow/AXLhigh invasive/ferroptosis-sensitive state. Mechanistically, ApoE secreted by the MITFhigh/AXLlow cells protects the invasive phenotype from ferroptosis-inducing agents by reducing the content of peroxidation-prone polyunsaturated fatty acids and boosting GPX4 levels both in vitro and in vivo. Whole-exome sequencing indicates that APOEhigh expression in patients with melanoma is associated with resistance to ferroptosis, regardless of APOE germline status. In aggregate, we found a ferroptosis-resistance mechanism between melanoma cell states relying on secreted ApoE and APOEhigh expression as a potential biomarker for poor ferroptosis response in melanoma.

Clinical Risk Factors of Subclinical Spread in Melanoma in Situ and Invasive Melanoma.

Clinical Risk Factors of Subclinical Spread in Melanoma in Situ and Invasive Melanoma.

Hunting for Early Melanomas With a Maximum Clinical Surface Diameter up to 6 mm: A Prospective Study of Reflectance Confocal Microscopy Features in 68 Consecutive Cases.

Early diagnosis of melanoma and prompt effective therapy optimizes prognosis. Reflectance confocal microscopy (RCM) facilitates diagnosis by providing immediate 3D single cell resolution down into the papillary dermis. Consecutive cases were examined using a Vivascope 1500 confocal microscope at a single referral medical practice in Sydney, Australia 2019-2023. Melanoma clinical surface diameters were recorded by 0.1 mm increments up to 6.0 mm. The RCM features recorded were: pagetoid single cells or nests, pleomorphic cell shape, atypical dendritic cells, non-edged papillae, variation in melanocyte size and confluent sheets of cells. All cases required diagnostic agreement by two dermatohistopathologists using hematoxylin and eosin staining followed by SOX 10 and/or PRAME stains if required. Total cases were 68: 38 males (mean age 57) and 30 females (mean age 64). Melanoma in situ (n = 65) compared to invasive melanoma (n = 3), all males, invasion depth (0.4-0.5 mm). Most frequent RCM features found in 50% or more of cases within all diameter increments were: pagetoid single cells n = 64/68 (94%), pleomorphic cell shape n = 63/68 (93%), epidermal disarray n = 58/68 (85%), and atypical dendritic cells n = 45/68 (66%). Non-edged dermal papillae were n = 42/68 (62%). Melanoma RCM features were found throughout the diameter ranges. Confocal examination may facilitate early melanoma recognition in these ranges.

Are Positive Biopsy Margins in Melanoma Significant?: A Cohort Study of Micro- Versus Macroscopic Margin Status and Their Impact on Residual Disease and Survival.

Presence of positive biopsy margins in melanoma can provoke anxiety over potential disease progression from delays to surgical excision, but their impact on outcomes is unknown. We aimed to compare the presence of residual melanoma in the surgical excision specimen and survival between patients with negative, microscopically positive, and macroscopically positive biopsy margins. Patients with cutaneous melanoma who underwent surgical excision over a 13-year period were included. Biopsy characteristics, residual disease in the surgical specimen, and overall and recurrence-free survival were compared between patients with negative, microscopically positive (only scar visible), and macroscopically positive (visible remaining melanoma) biopsy margins. Of 901 patients, 42.4%, 33.3%, and 24.3% had negative, microscopically positive, and macroscopically positive margins, respectively. The incidence of residual invasive melanoma in the surgical specimen varied (P < 0.001), occurring in 5.5%, 17.0%, and 74.9% of patients, respectively. Both microscopically and macroscopically positive margins were associated with residual disease (P < 0.001) but only the latter predicted worse overall (P = 0.013) and recurrence-free survival (P = 0.009). Kaplan-Meier estimated survival was comparable between those with negative and microscopically positive margins, but overall (P = 0.006) and recurrence-free survival (P = 0.004) were significantly worse in the macroscopically positive margin group. These patients had worse prognosis melanoma, with 33.8% being stage III disease, and 23.2% having positive sentinel lymph nodes. Patients and physicians may be reassured in the presence of microscopically positive biopsy margins which arenot associated with worse survival, However, patients with macroscopically positive margins have poorer prognosis and should be treated within an acceptable time frame.

Association of rurality and health professional shortages with the clinicopathologic characteristics of melanoma in North Carolina.

To assess rural-urban and health professional shortage area (HPSA)-related influences on the characteristics of melanoma in North Carolina. We conducted a single-center retrospective cohort study of patients living in North Carolina with an available pathology report for invasive cutaneous melanoma seen in the Duke University Health System from 01/01/2014 to 12/31/2020. Multivariable logistic regression models were employed to compare patient and tumor characteristics between rural versus urban county residence as well between melanoma thicknesses dichotomized into thin (≤1.0mm) and thicker (>1.0mm) tumors. The cohort included 807 patients, and rural patients accounted for 177 (21.9%) of invasive cutaneous melanomas. Rural patients had significantly higher odds of having thicker tumors than urban patients (odds ratio [OR] = 1.78, 95% confidence interval [CI]: 1.17-2.71; P =.008). Rural patients were significantly more likely to be female (OR = 1.59, 95% CI: 1.10-2.28; P =.013) and located in a population-based (OR = 2.66, 95% CI: 1.84-3.84; P<.001) or geographic-based (OR = 8.21, 95% CI: 3.33-20.22; P<.001) HPSA. Living in a medium- or high-shortage population-based HPSA was associated with higher odds of thicker tumors (OR = 2.65, 95% CI: 1.85-3.80; P<.001). Patients living in rural North Carolina counties were more likely than those in urban counties to be diagnosed with melanomas >1.0mm in thickness, a clinically significant difference with important prognostic implications. Interventions at the county- and state-level to address this disparity may include improving access to skin cancer screening and teledermatology programs, increasing partnerships with primary care providers, and targeting interventions to counties with health professional shortages.

Remote cutaneous confocal microscopy: A multicentric prospective study evaluating diagnostic accuracy for melanoma and keratinocyte carcinoma in tertiary settings

Cutaneous confocal microscopy (CCCM) facilitates in vivo visualisation of skin at a cellular level. Use of a "store and forward" approach for remote CCM interpretation (Remote-CCM) across multiple sites has not been tested and may increase access to non-invasive diagnosis. To test the diagnostic accuracy and safety of Remote-CCM. We prospectively recruited lesions selected for biopsy for skin malignancy across five Australian tertiary dermatology centres. CCM, clinical and dermoscopy images were acquired pre-biopsy and accessed by a cloud-based platform for interpretation by CCM readers. CCM diagnosis was compared to histopathology results. Amongst the 201 lesions included, melanoma was the most common malignancy (34/72, 47.2%). Of the 89 lesions (44.8%) potentially 'saved' from biopsy, 80 (90%) were truly benign lesions and 9 (10.1%) were missed malignant lesions of MIS (n=7) and SCC (n=2). No invasive melanomas were missed. Sensitivity of remote-CCM for detection of malignancy was 89% (95%CI 79-95%) and specificity was 64% (95%CI 55-73%). The study recruited from high-risk populations and excluded lesions that were not biopsied. Remote-CCM has comparable accuracy to bedside-CCM and safely reduces unnecessary biopsies. Potential SCCs are not appropriate for remote-CCM. Follow-up of borderline melanocytic lesions is recommended.

Mohs Micrographic Surgery With Melanocytic Immunostains for T1a/b Invasive Melanoma Yields

The use of Mohs micrographic surgery with melanocytic immunostains (MMS-I) for cutaneous melanoma is increasing. To assess local recurrence, melanoma-specific death rates in patients with invasive melanoma treated with MMS-I. A single-center retrospective review of patients with invasive melanoma treated with MMS-I from January 2008 to December 2018. Three hundred fifty-two patients (359 melanomas) were included. The median age was 71 years; most patients were male (252%; 71.6%). Most tumors were T1a/b (341, 95%), H/N (322; 89.7%), and lentigo maligna subtype (281, 78.3%). At a median follow-up of 4.3 years, local recurrence rates were 1.4% (5) and 0.9% (3) among all-stage and T1a/b tumors, respectively. There were 3 melanoma-related deaths (0.9%). MMS-I is associated with <1% risk of local recurrence and disease-specific mortality for T1a/b melanomas.

Extracellular vesicles from highly invasive melanoma subpopulations increase the invasive capacity of less invasive melanoma cells through mir-1246-mediated inhibition of CCNG2

Invasive growth is a critical process in tumor progression, requiring the activation of various molecular processes in tumor cells at the invasive front. Intercellular communication between heterogeneous tumor cells enhances cellular activation and adaptation to specific microenvironments. One mechanism of intercellular communication is the delivery of miRNAs through tumor cell-derived extracellular vesicles (EVs). In this context we have observed that conditioned media from a highly invasive cell subpopulation (BLM-HI) enhances the invasive capacity of the parental cell line (BLM). Therefore, we hypothesized that this complex change of cellular behavior is influenced by EV-transported miRNAs. The treatment of BLM cells with EVs derived from BLM-HI cells resulted in a significantly enhanced invasive capacity, as observed in Matrigel-embedded spheroids and in 2D Boyden chamber assays, with a dose-dependent effect. Conversely, the invasive capacity of BLM cells was reduced when secretion of EVs was inhibited by a sphingomyelinase inhibitor. To investigate the molecular mechanisms behind this effect, we performed next-generation sequencing and identified an enrichment of miR-1246 in these EVs. In functional analyses we demonstrated that both the EV mediated delivery of miR-1246 as well as overexpression contributes to the enhanced invasiveness of BLM cells. We identified a binding site of miR-1246 in the 3’UTR of cyclin G2 (CCNG2) and demonstrated direct binding by a luciferase reporter assay.Increased expression of CCNG2 has been associated with cancer metastasis and poor patient outcomes in other malignancies. Our study demonstrates that intercellular communication contributes to the transfer of properties, such as increased invasive capacity, between heterogeneous melanoma cells via EV-transported miRNAs.

Melanoma Incidence and Mortality Trends in Sweden.

Over the past decades, many global regions have experienced a steady increase in the incidence of cutaneous melanoma. However, more recently, a downward trend has been observed in the younger age groups in Australia and the US. Yet, in Europe, none of the countries have reported any significant decline in melanoma incidence for any age group. To assess melanoma incidence and mortality trends in Sweden, with a focus on individuals younger than the average age of melanoma onset. This cohort study used data on the national population from the Swedish Melanoma Registry and the Swedish Cancer Registry, which cover more than 99% of all primary invasive cutaneous melanomas diagnosed in the country. All patients diagnosed from 1990 to 2022 were included. Incidence and mortality rates per 100 000 inhabitants were calculated for each year and shown as average annual rates for every 5-year period from 1990 to 2022. Joinpoint regression models were used to evaluate statistical significance of temporal trends and points of change. There were 34 800 primary invasive cutaneous melanomas (19 582 [56.3%] in females and 15 218 [43.7%] in males) reported in 33 324 individuals younger than 60 years (median [IQR] age, 48 [36-58] years) from 1990 to 2022. A consistent rise in melanoma incidence was observed among those 50 to 59 years old. The age groups from 20 to 29 years, 30 to 39 years, and 40 to 49 years showed an incidence peak in 2013 to 2015 followed by stable or significantly declining rates until 2022. In patients younger than 20 years, melanoma incidence remained low with no significant trends. There was also a significant decline in melanoma mortality among 30- to 59-year-old individuals, but not in those 60 years and older. The findings of this cohort study showed a significant recent downward trend in both melanoma incidence and melanoma mortality in the age group 30 to 49 years in Sweden. The reasons for these declines are unclear but may include UV protection, public health campaigns, changing population demographics, and the introduction of effective melanoma treatment. None of these possibilities were evaluated; further study is needed.

Sex-dependent effects in the aged melanoma tumor microenvironment influence invasion and resistance to targeted therapy

There is documented sex disparity in cutaneous melanoma incidence and mortality, increasing disproportionately with age and in the male sex. However, the underlying mechanisms remain unclear. While biological sex differences and inherent immune response variability have been assessed in tumor cells, the role of the tumor-surrounding microenvironment, contextually in aging, has been overlooked. Here, we show that skin fibroblasts undergo age-mediated, sex-dependent changes in their proliferation, senescence, ROS levels, and stress response. We find that aged male fibroblasts selectively drive an invasive, therapy-resistant phenotype in melanoma cells and promote metastasis in aged male mice by increasing AXL expression. Intrinsic aging in male fibroblasts mediated by EZH2 decline increases BMP2 secretion, which in turn drives the slower-cycling, highly invasive, and therapy-resistant melanoma cell phenotype, characteristic of the aged male TME. Inhibition of BMP2 activity blocks the emergence of invasive phenotypes and sensitizes melanoma cells to BRAF/MEK inhibition.

Pannexin 1 crosstalk with the Hippo pathway in malignant melanoma.

In this study, we explored the intricate relationship between Pannexin 1 (PANX1) and the Hippo signaling pathway effector, Yes-associated protein (YAP). Analysis of The Cancer Genome Atlas (TCGA) data revealed a significant positive correlation between PANX1 mRNA and core Hippo components, YAP, TAZ, and Hippo scaffold, IQGAP1, in invasive cutaneous melanoma and breast carcinoma. Furthermore, we demonstrated that PANX1 expression is upregulated in invasive melanoma cell lines and is associated with increased YAP protein levels. Notably, our investigations uncovered a previously unrecognized interaction between endogenous PANX1 and the Hippo scaffold protein IQGAP1 in melanoma cells. Moreover, our findings revealed that IQGAP1 exhibits differential expression in melanoma cells and plays a regulatory role in cellular morphology. Functional studies involving PANX1 knockdown provided compelling evidence that PANX1 modulates YAP protein levels and its co-transcriptional activity in both melanoma and breast carcinoma cells. Importantly, our study showcases the potential therapeutic relevance of targeting PANX1, as pharmacological inhibition of PANX1 using selective FDA-approved inhibitors or PANX1 knockdown reduced YAP abundance in melanoma cells. Furthermore, our Clariom™ S analysis unveiled key genes implicated in cell proliferation, such as neuroglin1 (NRG1), β-galactoside binding protein, galectin-3 (LGALS3), that are affected in PANX1-deficient cells. In summary, our investigation delves into the intricate interplay between PANX1 and YAP in the context of invasive melanoma, offering valuable insights into potential therapeutic strategies for effective treatment.

Trends in Invasive Melanoma Thickness in Norway, 1983-2019.

Monitoring melanoma incidence time trends by tumour thickness is essential to understanding the evolution of melanoma occurrence and guiding prevention strategies. To assess long-term incidence trends, tumour thickness was extracted from pathology reports in the Cancer Registry of Norway (1983-2007) and the Norwegian Melanoma Registry (2008-2019), n = 45,635 patients. Across all anatomic sites, T1 (≤ 1 mm) incidence increased most (men annual percentage change [AAPC] = 4.6, 95% confidence interval [95% CI] 4.2-5.0; women AAPC = 3.2, 95% CI 2.8-3.6); the increase was steep until 1989/90, followed by a plateau, and a further steep increase from 2004/05. Increased incidence was also observed for T2 (>1.0-2.0) melanoma (men AAPC = 2.8, 95% CI 2.4-3.2; women AAPC = 1.5, 95% CI 1.1-1.9), and T3 (>2.0-4.0) in men (AAPC = 1.4, 95% CI 0.9-1.9). T4 (>4.0) melanoma followed a similar overall pattern (men AAPC = 1.3, 95% CI 0.9-1.7, head/neck, upper limbs, and trunk; women AAPC = 0.9, 95% CI 0.4-1.4, upper limbs and trunk). Men had the highest T3 and T4 incidence and the sex difference increased with age. Regarding birth cohorts, age-specific incidence increased in all T categories in the oldest age groups, while stabilizing in younger patients born after 1950. Overall, the steep increase in T1 melanoma was not accompanied by a decrease in thick melanoma.

52451 Intraoperative immunohistochemistry during Mohs micrographic surgery and staged excision decreases local recurrence rates for invasive cutaneous melanoma: A systematic review and meta-analysis

52451 Intraoperative immunohistochemistry during Mohs micrographic surgery and staged excision decreases local recurrence rates for invasive cutaneous melanoma: A systematic review and meta-analysis

Changes in the incidence of melanoma in Australia, 2006-2021, by age group and ancestry: a modelling study.

To estimate the incidence of melanoma in Australia among people with ancestries associated with low, moderate, or high risk of melanoma, by sex and 5-year age group; to establish whether age-specific incidence rates by ancestry risk group have changed over time. Modelling study; United States (SEER database) melanoma incidence rates for representative ancestral populations and Australian census data (2006, 2011, 2016, 2021) used to estimate Australian melanoma incidence rates by ancestry-based risk. Australia, 2006-2021. Age-specific invasive melanoma incidence rates, and average annual percentage change (AAPC) in age-specific melanoma rates, by ancestry-based risk group, sex, and 5-year age group. The proportion of people in Australia who reported high risk (European) ancestry declined from 85.3% in 2006 to 71.1% in 2021. The estimated age-standardised melanoma incidence rate was higher for people with high risk ancestry (2021: males, 82.2 [95% confidence interval {CI}, 80.5-83.8] cases per 100 000 population; females, 58.5 [95% CI, 57.0-59.9] cases per 100 000 population) than for all Australians (males, 67.8 [95% CI, 66.5-69.2] cases per 100 000 population; females, 45.4 [95% CI, 44.3-46.5] cases per 100 000 population). AAPCs were consistently positive for Australians aged 50 years or older, both overall and for people with high risk ancestry, but were statistically significant only for some age groups beyond 65 years. AAPCs were negative for people aged 34 years or younger, but were generally not statistically significant. Melanoma incidence has declined in some younger age groups in Australia, including among people with high risk ancestry. Social and behavioural changes over the same period that lead to lower levels of ultraviolet radiation exposure probably contributed to these changes.

52819 Enabling access to prognostic gene expression profile (GEP) testing for invasive melanoma by leveraging RNA-based testing in the diagnostic workflow

52819 Enabling access to prognostic gene expression profile (GEP) testing for invasive melanoma by leveraging RNA-based testing in the diagnostic workflow