Baseline Serum neutrophil-to-lymphocyte ratio in acral melanoma compared with nonacral melanoma and its prognostic significance

BACKGROUND

Acral lentiginous melanoma (ALM), a cutaneous melanoma subtype, exhibits a poorer prognosis than nonacral cutaneous melanoma (NACM). The neutrophil-to-lymphocyte ratio (NLR) is emerging as a prognostic indicator across diverse cancers.

OBJECTIVE

We explored the baseline NLR disparities between ALM and NACM, and the NLR's prognostic significance in patients with ALM.

METHODS

We reviewed records of patients with ALM and NACM diagnosed between 1997 and 2022, analyzing medical data.

RESULTS

Among 327 and 159 patients with ALM and NACM, respectively, baseline NLR varied based on distinct clinicopathologic factors between ALM and NACM. In stage 3 to 4 melanomas, the median NLR for ALM (2.18; IQR, 1.70-3.08) significantly surpassed NACM (1.74; IQR, 1.33-2.53) (P = .029). In patients with ALM, high NLR (hazard ratio, 1.64; 95% CI, 1.02-2.66; P = .043) was independently correlated with poor progression-free survival when adjusting for ulceration, Breslow thickness of ≥2 mm, and nodal invasion.

LIMITATIONS

Single-center, retrospective design.

CONCLUSION

Advanced-stage ALM exhibited a significantly higher baseline NLR compared with that of NACM. Evaluating baseline NLR could provide valuable prognostic insights for patients with ALM.

Corrigendum: The utility of high-frequency 18 MHz ultrasonography for preoperative evaluation of acral melanoma thickness in Chinese patients

[This corrects the article DOI: 10.3389/fonc.2023.1185389.].

Optimal strategy in managing advanced melanoma

The advent of immune checkpoint inhibitors and combination therapy with BRAF inhibitors and MEK inhibitors has dramatically improved the prognosis of advanced melanoma. However, since acral melanoma and mucosal melanoma, which are rare in Western countries but are major subtypes of melanoma in East Asia, including Japan, have a low frequency of BRAF mutations, there are currently no treatment options other than immune checkpoint inhibitors in most such cases. Furthermore, owing to a lower tumor mutation burden, immune checkpoint inhibitors are less effective in acral and mucosal melanoma than in cutaneous melanoma. The aim of this review was to summarize the current status and future prospects for the treatment of advanced melanoma, comparing cutaneous melanoma, acral melanoma, and mucosal melanoma.

Multidisciplinary approach and treatment of acral and mucosal melanoma

Acral and mucosal melanoma are uncommon variants of melanoma. Acral melanoma has an age-adjusted incidence of approximately 1.8 cases per million individuals per year, accounting for about 2% to 3% of all melanoma cases. On the other hand, mucosal melanoma, with an incidence of 2.2 cases per million per year, makes up around 1.3% of all melanoma cases. These melanomas, in addition to being biologically and clinically distinct from cutaneous melanoma, share certain clinical and pathologic characteristics. These include a more aggressive nature and a less favorable prognosis. Furthermore, they exhibit a different mutational pattern, with KIT mutations being more prevalent in acral and mucosal melanomas. This divergence in mutational patterns may partially account for the relatively poorer prognosis, particularly to immune checkpoint inhibitors. This review explores various aspects of acral and mucosal melanoma, including their clinical presentation, pathologic features, mutational profiles, current therapeutic approaches, outcomes associated with systemic therapy, and potential strategies to address resistance to existing treatments.

A European Multicentric Investigation of Atypical Melanocytic Skin Lesions of Palms and Soles: The iDScore-PalmoPlantar Database

Background: The differential diagnosis of atypical melanocytic palmoplantar skin lesions (aMPLs) represents a diagnostic challenge, including atypical nevi (AN) and early melanomas (MMs) that display overlapping clinical and dermoscopic features. We aimed to set up a multicentric dataset of aMPL dermoscopic cases paired with multiple anamnestic risk factors and demographic and morphologic data. Methods: Each aMPL case was paired with a dermoscopic and clinical picture and a series of lesion-related data (maximum diameter value; location on the palm/sole in 17 areas; histologic diagnosis; and patient-related data (age, sex, family history of melanoma/sunburns, phototype, pheomelanin, eye/hair color, multiple/dysplastic body nevi, and traumatism on palms/soles). Results: A total of 542 aMPL cases-113 MM and 429 AN-were collected from 195 males and 347 females. No sex prevalence was found for melanomas, while women were found to have relatively more nevi. Melanomas were prevalent on the heel, plantar arch, and fingers in patients aged 65.3 on average, with an average diameter of 17 mm. Atypical nevi were prevalent on the plantar arch and palmar area of patients aged 41.33 on average, with an average diameter of 7 mm. Conclusions: Keeping in mind the risk profile of an aMPL patient can help obtain a timely differentiation between malignant/benign cases, thus avoiding delayed and inappropriate excision, respectively, with the latter often causing discomfort/dysfunctional scarring, especially at acral sites.

Management of acral lentiginous melanoma: current updates and future directions

Acral lentiginous melanoma is a rare subtype of melanoma generally associated with poor outcomes, even when diagnosed at an early stage. The tumor genetic profile remains poorly understood, but it is known to have a suppressed immune environment compared to that of non-acral cutaneous melanomas, which limits therapy options. There is significant attention on the development of novel therapeutic approaches, although studies are limited due to disease rarity. For local disease, wide local excision remains the standard of care. Due to frequent under-staging on preoperative biopsy, wider margins and routine sentinel lymph node biopsy may be considered if morbidity would not be increased. For advanced disease, anti-PD1 monotherapy or combination therapy with anti-PD1 and anti-CTLA4 agents have been used as first-line treatment modalities. Anti-PD1 and anti-CTLA4 combination therapies have been shown to be particularly beneficial for patients with BRAF-mutant acral lentiginous melanoma. Other systemic combination regimens and targeted therapy options may be considered, although large studies with consistent results are lacking. Regional and intralesional therapies have shown promise for cutaneous melanomas, but studies generally have not reported results for specific histologic subtypes, especially for acral melanoma. Overall, the unique histologic and genetic characteristics of acral lentiginous melanoma make therapy options significantly more challenging. Furthermore, studies are limited, and data reporting has been inconsistent. However, more prospective studies are emerging, and alternative therapy pathways specific to acral lentiginous melanoma are being investigated. As further evidence is discovered, reliable treatment guidelines may be developed.

PRAME Updated: Diagnostic, Prognostic, and Therapeutic Role in Skin Cancer

Preferentially Expressed Antigen in Melanoma (PRAME), a member of the cancer/testis antigen family, is central to the field of skin cancer diagnostics and therapeutics. As a nuclear receptor and transcriptional regulator, PRAME plays a critical role in inhibiting retinoic acid signalling, which is essential for cell differentiation and proliferation. Its aberrant overexpression in various malignancies, particularly cutaneous melanoma, is associated with more aggressive tumour phenotypes, positioning PRAME as both a diagnostic and prognostic marker. In melanoma, PRAME is typically highly expressed, in contrast to its weak or absent expression in benign nevi, thereby improving the accuracy of differential diagnoses. The diagnostic value of PRAME extends to various lesions. It is significantly expressed in uveal melanoma, correlating to an increased risk of metastasis. In acral melanomas, especially those with histopathological ambiguity, PRAME helps to improve diagnostic accuracy. However, its expression in spitzoid and ungual melanocytic lesions is inconsistent and requires a comprehensive approach for an accurate assessment. In soft tissue sarcomas, PRAME may be particularly helpful in differentiating melanoma from clear cell sarcoma, an important distinction due to their similar histological appearance but different treatment approaches and prognosis, or in detecting dedifferentiated and undifferentiated melanomas. In non-melanoma skin cancers such as basal cell carcinoma, squamous cell carcinoma, and Merkel cell carcinoma, the variable expression of PRAME can lead to diagnostic complexity. Despite these challenges, the potential of PRAME as a therapeutic target in melanoma is significant. Emerging immunotherapies, including T-cell-based therapies and vaccines targeting PRAME, are being investigated to exploit its cancer-specific expression. Ongoing research into the molecular role and mechanism of action of PRAME in skin cancer continues to open new avenues in both diagnostics and therapeutics, with the potential to transform the management of melanoma and related skin cancers.

A real-world study on the safety profile of extended-interval dosing of immune checkpoint inhibitors for melanoma: a single-center analysis in Japan

Background

Anti-programmed death-1 (PD-1) antibodies are the mainstay for the treatment of unresectable or high-risk melanoma. However, real-world data on the safety profile of their extended-interval doses (EDs) are limited, particularly in Asian patients with melanoma.

Materials and methods

In this single-center retrospective study, we analyzed the risks of immune-related adverse events (irAEs) among 71 Japanese patients (36 males; mean age, 65.0 years) who received anti-PD-1 monotherapy for melanoma at our institute. Patients who were administered ipilimumab prior to anti-PD-1 monotherapy were excluded. Patients were divided into three groups: canonical-interval dose (CD) group (n = 50, body weight-based dosing or 240 mg Q2W for nivolumab and body weight-based dosing or 200 mg Q3W for pembrolizumab), ED group (n = 14, 480 mg Q4W for nivolumab and 400 mg Q6W for pembrolizumab), and dose-switch (DS) group (n = 7, upfront CD followed by ED).

Results

The CD group received nivolumab more frequently in the metastatic setting. There were no significant differences in baseline characteristics among the three groups, including in sex, age, primary tumor site, tumor subtype, and follow-up period. irAEs occurred in 36.6% (26 patients) of all patients (32.0% of the CD group, 35.7% of the ED group, and 71.4% of the DS group), while severe (grade ≥ 3) irAEs occurred in only two patients, both of whom were in the CD group. Most of the irAEs occurred during the first 6 months of anti-PD-1 therapy and, interestingly, all of the irAEs in the DS group occurred before the switch (during the CD). There was no significant difference among the three groups in the probability of irAE estimated by the Kaplan-Meier method.

Conclusion

These findings may highlight the safety of ED of anti-PD-1 monotherapy in the treatment of Asian patients with melanoma.

Compound clear cell sarcoma with EWSR1::CREM fusion

Cutaneous clear cell sarcomas may be confused with melanomas as a result of overlapping histopathology and immunohistochemical staining. We report a case of a 41-year-old woman with a purported history of acral melanoma of the great toe. Twenty-one months after excision of the primary tumor, the patient developed a groin mass, diagnosed as metastatic melanoma on excision. Five months later, a biopsy of a lung mass was reported as metastatic melanoma. The patient was referred to our institution for treatment, which prompted molecular testing on the groin metastasis by targeted next-generation sequencing. Molecular testing results revealed TP53 and TERT promoter mutations and the absence of BRAF, KRAS, and KIT mutations; it also revealed an EWSR1::CREM fusion that was confirmed by Archer FusionPlex. The alleged acral melanoma was re-reviewed, showing an invasive amelanotic spindle cell neoplasm in the dermis with neoplastic nests at the dermal-epidermal junction; the tumor cells expressed markers of melanocytic differentiation but were negative for PRAME and BRAF immunohistochemical staining. Molecular testing of the toe and lung metastasis revealed the same EWSR1::CREM fusion. In light of the molecular findings, the diagnosis was revised to a primary acral compound clear cell sarcoma with EWSR1::CREM fusion.

Prediction of nonsentinel lymph node metastasis in acral melanoma with positive sentinel lymph nodes

BACKGROUND

Metastasis in a nonsentinel lymph node (non-SLN) is an unfavorable independent prognostic factor in cutaneous melanoma (CM). Recent data did suggest potential value of completion lymph node dissection (CLND) in CM patients with non-SLN metastasis. Prediction of non-SLN metastasis assists clinicians in deciding on adjuvant therapy without CLND. We analyzed risk factors and developed a prediction model for non-SLN status in acral melanoma (AM).

METHODS

This retrospective study enrolled 656 cases of melanoma who underwent sentinel lymph node biopsy at Fudan University Shanghai Cancer Center from 2009 to 2017. We identified 81 SLN + AM patients who underwent CLND. Clinicopathologic data, including SLN tumor burden and non-SLN status were examined with Cox and Logistics regression models.

RESULTS

Ulceration, Clark level, number of deposits in the SLN (NumDep) and maximum size of deposits (MaxSize) are independent risk factors associated with non-SLN metastases. We developed a scoring system that combines ulceration, the cutoff values of Clark level V, MaxSize of 2 mm, and NumDep of 5 to predict non-SLN metastasis with an efficiency of 85.2% and 100% positive predictive value in the high-rank group (scores of 17-24).

CONCLUSIONS

A scoring system that included ulceration, Clark level, MaxSize, and NumDep is reliable and effective for predicting non-SLN metastasis in SLN-positive AM.

Reconstruction of plantar surgical defects with synthetic dermal matrix and split-thickness skin grafts: A case series and functional podiatry outcomes

Reconstruction of surgical defects after wide local excision of acral melanoma on the sole should allow patients to walk and bear weight. Moreover, certain options such as local transposition flaps can compromise follow-up. We present a case series of surgical defects on weight-bearing areas of the sole reconstructed using a synthetic dermal matrix and a split-thickness skin graft. This approach prevents surrounding tissue displacement and results in good functional outcomes assessed by baropodometry and computer-based podoscopy.

Differential gradients of immunotherapy vs targeted therapy efficacy according to the sun-exposure pattern of the site of occurrence of primary melanoma: a multicenter prospective cohort study (MelBase)

Background

The tumor mutational burden (TMB) is high in melanomas owing to UV-induced oncogenesis. While a high TMB is a predictive biomarker of response to PD-1 inhibitors, it may be associated with the rise of resistant clones to targeted therapy over time. We hypothesized that survivals may depend on both the sun-exposure profile of the site of primary melanoma and the type of systemic treatment.

Patients and methods

Patients were screened from MelBase, a multicenter biobank dedicated to the prospective follow-up of stage III/IV melanoma. All patients with a known cutaneous primary melanoma who received a 1st-line systemic treatment by immunotherapy or targeted therapy were included (2013-2019). Outcomes were progression-free survival (PFS) and overall survival (OS).

Results

973 patients received either anti PD-1(n=466), anti CTLA-4(n=143), a combination of both (n=118), or targeted therapies (n=246). Patients' characteristics at treatment initiation were: male (62%), median age of 62, AJCC stage IV (84%). Median follow-up was 15.5 months. The primary melanoma was located on chronically sun-exposed skin in 202 patients (G1: head neck), on intermittently sun-exposed skin in 699 patients (G2: trunk, arms, legs), and on sun-protected areas in 72 patients (G3: palms, soles). Median PFS was significantly higher in G1 under anti PD-1 treatment (8.7 months vs 3.3 and 3.4 months for G2 and G3, respectively) (p=0.011). PFS did not significantly differ in other groups. Similarly, median OS was significantly higher in G1 receiving 1st line anti PD-1 treatment (45.6 months vs 31.6 and 21.4 months for G2 and G3) (p=0.04), as opposed to 1st line targeted therapy (19.5 months vs 16.3 and 21.1 months for G1, G2 and G3 respectively).

Conclusion

Our study confirms that immunotherapy with anti PD-1 is particularly recommended for melanomas originating from chronically sun-exposed areas, but this finding needs to be confirmed by further research.

The utility of high-frequency 18 MHz ultrasonography for preoperative evaluation of acral melanoma thickness in Chinese patients

Background

Despite the increasing use of preoperative ultrasound evaluation for melanoma, there is limited research on the use of this technique for Acral Melanoma (AM).

Methods

This retrospective study analyzed the electronic medical records of patients who underwent preoperative evaluation for cutaneous melanoma maximum thickness using an 18 MHz probe and histopathological examination between December 2017 and March 2021 at the Department of Dermatology in Xiangya Hospital, Central South University.

Results

A total of 105 patients were included in the study. The mean tumor thickness was 3.9 mm (s.d., 2.3), with 63% of the specimens showing ulceration and 44 patients showing lymph node metastasis. The results showed a good correlation between the high-frequency ultrasonography (HFUS) and histopathological thickness measurements, with a Spearman's correlation coefficient of 0.83 [(95% CI 0.73-0.90) (P < 0.001)]. The positive predictive value (PPV) of sonography in identifying tumor thickness was also found to be high.

Conclusion

Our study suggests that high-frequency 18 MHz ultrasonography is an effective tool for the preoperative evaluation of AM thickness. The HFUS measurements correlated well with the histopathological thickness measurements, making it a valuable and reliable method for clinicians to assess the thickness of melanoma lesions preoperatively.

PAK1 and Therapy Resistance in Melanoma

Malignant melanoma claims more lives than any other skin malignancy. While primary melanomas are usually cured via surgical excision, the metastatic form of the disease portents a poor prognosis. Decades of intense research has yielded an extensive armamentarium of anti-melanoma therapies, ranging from genotoxic chemo- and radiotherapies to targeted interventions in specific signaling pathways and immune functions. Unfortunately, even the most up-to-date embodiments of these therapies are not curative for the majority of metastatic melanoma patients, and the need to improve their efficacy is widely recognized. Here, we review the reports that implicate p21-regulated kinase 1 (PAK1) and PAK1-related pathways in the response of melanoma to various therapeutic modalities. Ample data suggest that PAK1 may decrease cell sensitivity to programmed cell death, provide additional stimulation to growth-promoting molecular pathways, and contribute to the creation of an immunosuppressive tumor microenvironment. Accordingly, there is mounting evidence that the concomitant inhibition of PAK1 enhances the potency of various anti-melanoma regimens. Overall, the available information suggests that a safe and effective inhibition of PAK1-dependent molecular processes would enhance the potency of the currently available anti-melanoma treatments, although considerable challenges in implementing such strategies still exist.

Differences in the Clinical and Molecular Profiles of Subungual Melanoma and Acral Melanoma in Asian Patients

Subungual melanoma (SUM) is a rare type of malignant melanoma that arises beneath the nails. SUM is categorized as a type of acral melanoma (AM), which occurs on the hands and feet. SUM is an aggressive type of cutaneous melanoma that is most common among Asian patients. Recent studies reveal that SUM and AM might have different molecular characteristics. Treatment of melanoma relies on analysis of both clinical and molecular data. Therefore, the clinical and molecular characteristics of SUM need to be established, especially during metastasis. To define the mutation profiles of SUM and compare them with those of AM, we performed next-generation sequencing of primary and metastatic tumors of SUM and AM patients. Subungual location was a better independent prognostic factor than acral location for better overall survival (p = 0.001). Patients with SUM most commonly had the triple wild-type (75%) driven by GNAQ (58%) and KIT (25%) mutations, whereas patients with AM had BRAF (28.6%) and RAF (14.3%) molecular types of mutations. Single-nucleotide variations (SNVs) were more common in SUM than in AM, whereas copy number alterations (CNAs) were more common metastatic lesions of AM. Metastatic tumors in patients with SUM and AM showed increases in CNAs (43% and 80%, respectively), but not in SNVs. The number of CNAs increased during metastasis. When compared with AM, SUM has distinct clinical and molecular characteristics.

Telomerase reverse transcriptase immunohistochemical expression is sensitive but not specific for TERT gene amplification in acral melanoma

BACKGROUND

TERT gene amplification (TGA) is a mechanism of telomerase reverse transcriptase (TERT) upregulation frequently utilized by acral melanomas (AMs). Currently, the utility of TERT immunohistochemistry (IHC) to predict TGA status in AMs is poorly documented.

METHODS

AMs (26 primary and 3 metastatic) and non-acral cutaneous melanomas (6 primary) were subjected to immunohistochemical analysis using anti-TERT antibody to demonstrate protein expression and fluorescence in situ hybridization (FISH) to assess genomic copy number alteration. The relationship between TERT immunoreactivity and TGA confirmed by FISH was assessed using logistic regression.

RESULTS

TERT expression was seen in 50% (13/26) of primary and 100% (3/3) of metastatic AMs and 50% (3/6) of primary non-acral cutaneous melanomas. TGA was found in 15% (4/26) and 67% (2/3) of primary and metastatic AMs and 17% (1/6) of non-acral cutaneous melanomas. The intensity of TERT immunoreactivity correlated with TGA (p = 0.04) and a higher TERT copy number-to-control ratio in AMs, with a correlation coefficient of 0.41 (p = 0.03). The sensitivity and specificity of TERT immunoreactivity for predicting TGA in AMs were 100% and 57%, with corresponding positive and negative predictive values of 38% and 100%, respectively.

CONCLUSIONS

The clinical utility of TERT IHC to predict TGA status in AMs appears to be limited given its low specificity and positive predictive value.

Combined tumour of aberrant cytokeratin expressing acral lentiginous melanoma and poroma: Diagnostic challenge

Combined tumours are uncommon and therefore these tumours may pose a diagnostic challenge. In the current case report, it is aimed to present the clinicopathological features of a combined tumour including melanoma with aberrant cytokeratin expression and poroma.

Adult and Pediatric Nail Unit Melanoma: Epidemiology, Diagnosis, and Treatment

Nail unit melanoma (NUM) is an uncommon form of melanoma and is often diagnosed at later stages. Approximately two-thirds of NUMs are present clinically as longitudinal melanonychia, but longitudinal melanonychia has a broad differential diagnosis. Clinical examination and dermoscopy are valuable for identifying nail findings concerning malignancy, but a biopsy with histopathology is necessary to confirm a diagnosis of NUM. Surgical treatment options for NUM include en bloc excision, digit amputation, and Mohs micrographic surgery. Newer treatments for advanced NUM include targeted and immune systemic therapies. NUM in pediatric patients is extremely rare and diagnosis is challenging since both qualitative and quantitative parameters have only been studied in adults. There is currently no consensus on management in children; for less concerning melanonychia, some physicians recommend close follow-up. However, some dermatologists argue that the "wait and see" approach can cause delayed diagnosis. This article serves to enhance the familiarity of NUM by highlighting its etiology, clinical presentations, diagnosis, and treatment options in both adults and children.

Single-Cell RNA Sequencing Reveals Cellular Heterogeneity in an Acral Amelanotic Melanoma After Immunotherapy Treatment

Background

Anti-programmed cell death ligand-1 (anti-PD-L1) immunotherapy is often used for advanced urothelial carcinoma and melanoma, including amelanotic melanoma, a relatively rare subtype with little to no pigment in the tumor cells. However, cellular heterogeneity of amelanotic melanoma during or after anti-PD-L1 immunotherapy treatments has not been described.

Purpose

To investigate cellular heterogeneity in acral amelanotic melanoma after immunotherapy exposure.

Methods

We evaluated subtle visual changes of the melanoma by dermoscopy and performed a pathological examination to analyze the heterogeneity of microscopic morphological and immunohistochemistry changes. The cellular transcriptional heterogeneity and corresponding biological function profiles of the melanoma were determined by single-cell RNA sequencing (scRNA-seq).

Results

The dermoscopic examination revealed black globules and scar-like depigmentation areas against a homogeneous red background. Pigmented and amelanotic melanoma cells were observed microscopically. The pigmented cells were large and contained melanin granules expressing Melan-A and HMB45; the amelanotic cells were small and did not express HMB45. Ki-67 immunohistochemical staining revealed that the pigmented melanoma cells had a higher proliferative ability than the amelanotic cells. scRNA-seq identified three cell clusters: amelanotic cell cluster 1, amelanotic cell cluster 2, and pigmented cell cluster. Furthermore, a pseudo-time trajectory analysis showed that amelanotic cell cluster 2 originated from amelanotic cell cluster 1 and transformed into the pigmented melanoma cell cluster. The expression pattern of melanin synthesis-related and lysosome-endosome-related genes in different cell clusters supported the cell cluster transformation results. Also, upregulated expression of cell cycle genes indicated that the pigmented melanoma cells had a high proliferative ability.

Conclusion

Coexisting amelanotic and pigmented melanoma cells indicated cellular heterogeneity in an acral amelanotic melanoma from a patient who underwent immunotherapy treatment. Additionally, the pigmented melanoma cells acquired a higher proliferative ability than the amelanotic melanoma cells.

Prognostic impact of Breslow thickness in acral melanoma: A retrospective analysis

BACKGROUND

Evidence for the prognostic importance of tumor thickness in acral melanoma (AM) patients is limited.

OBJECTIVE

The objective of the study was to determine the prognostic impact of Breslow thickness in AM.

METHODS

This multicenter study enrolled patients diagnosed with localized AM between January 1, 2000 and December 31, 2017. Melanoma-specific survival (MSS) in different tumor thickness strata (T1-T4: ≤1, >1-2, >2-4, >4 mm, respectively) was estimated by the Kaplan-Meier method. Comparisons were performed by the log-rank test and multivariable Cox regression.

RESULTS

A total of 853 patients with clinical N0 (cN0) AM were included in the analysis. The median follow-up time was 60.1 months. The median MSS in patients with T1-T4 disease was not reached, 111.0, 92.8, and 67.1 months, respectively. MSS differed significantly among cN0 patients with T1-T3 AM (log-rank P = .004, .012, <0.001 for T1 vs T2, T2 vs T3, and T1 vs T3, respectively); however, there was no significant difference between T3 and T4 AM (hazard ratio = 0.82, 95% CI, 0.62-1.09). Six-subgroup analyses confirmed that survival outcomes were similar between different subgroups with tumor thickness >2 mm.

LIMITATIONS

The limitations were retrospective design and some missing variables.

CONCLUSIONS

There was no association between tumor thickness and survival in AM patients with a Breslow thickness >2 mm.

YAP Activation in Promoting Negative Durotaxis and Acral Melanoma Progression

Directed cell migration towards a softer environment is called negative durotaxis. The mechanism and pathological relevance of negative durotaxis in tumor progression still requires in-depth investigation. Here, we report that YAP promotes the negative durotaxis of melanoma. We uncovered that the RhoA-myosin II pathway may underlie the YAP enhanced negative durotaxis of melanoma cells. Acral melanoma is the most common subtype of melanoma in non-Caucasians and tends to develop in a stress-bearing area. We report that acral melanoma patients exhibit YAP amplification and increased YAP activity. We detected a decreasing stiffness gradient from the tumor to the surrounding area in the acral melanoma microenvironment. We further identified that this stiffness gradient could facilitate the negative durotaxis of melanoma cells. Our study advanced the understanding of mechanical force and YAP in acral melanoma and we proposed negative durotaxis as a new mechanism for melanoma dissemination.

Hyperplastic melanocytes with chromosomal aberrations in surrounding skin of subungual melanoma: fluorescence in situ hybridization analysis using whole-slide digital imaging

AIMS

Subungual melanoma (SUM) is increasingly being treated with conservative surgery. Consequently, the evaluation of resection margins has increased in importance. However, in several cases it is difficult to distinguish the in-situ lesion of SUM from hyperplastic melanocytes in surrounding skin. We examined whether PReferentially expressed Antigen in MElanoma (PRAME) immunohistochemistry and fluorescence in situ hybridization (FISH) labeling of CCND1 (11q13), RREB1 (6p25), MYB (6q23), and centromere 6 (CEP6) genes differentiated SUM from hyperplastic melanocytes.

METHODS AND RESULTS

We reviewed specimens of 36 SUM cases and compared PRAME immunostains of invasive melanoma, melanoma in situ, and hyperplastic melanocytes. PRAME-positive cases accounted for 90.5% of invasive melanoma, 88.9% of in situ melanoma, and 59.4% of hyperplastic melanocyte specimens. While invasive and in situ melanomas in more than half of examined cases were diffusely positive, this was found for only 9.4% of hyperplastic melanocyte cases. Four-colored FISH using whole-slide digital imaging was used to analyze positive detection rates and changes in chromosomal aberrations. The FISH positive detection rate was 100% in invasive melanomas, 94.7% in melanomas in situ, and 66.7% in hyperplastic melanocytes. The number of RREB1 (6p25) signals per cell was significantly amplified following tumor progression.

CONCLUSION

Hyperplastic melanocytes in the surrounding skin of SUM, considered morphologically non-neoplastic, showed chromosomal aberrations similar to those in melanoma. Such cells are also thought similar to the field cells of acral melanomas. Thus, whole-slide digital imaging is a technique that allows the evaluation of individual melanocyte lesions by FISH.

Acral Melanocytic Neoplasms: A Comprehensive Review of Acral Nevus and Acral Melanoma in Asian Perspective

Acral melanocytic neoplasms, including acral melanocytic nevus and acral melanoma, are common melanocytic lesions in Asian populations. Both lesions occur on the volar surface of the hands and feet, and on nail units. Acral melanocytic nevi occur on the arch area of the sole, whereas acral melanomas frequently occur on weight-bearing areas of the sole, and on the fingernails. Therefore, the development of acral melanoma may be associated with chronic pressure, physical stress, or trauma. Dermoscopy is a useful adjunctive diagnostic tool for differential diagnosis. Acral melanocytic nevus is characterized by a parallel furrow pattern, whereas acral melanoma has a parallel ridge pattern. Genetic alterations are also different between the two types of lesion. BRAF and NRAS mutations are common in acral melanocytic nevus, whereas acral melanoma shows lower rates of KIT, NF1, BRAF, and NRAS mutations and remarkable copy number variations in genes such as CCND1, CDK4, hTERT, PAK1, and GAB2. Sentinel lymph node biopsy is important for staging and prognosis. Contemporary treatments for melanoma include targeted therapy for mutations and immunotherapy, such as anti-PD1 inhibitors.

Adjuvant Anti-PD-1 Antibody Therapy for Advanced Melanoma: A Multicentre Study of 78 Japanese Cases

Anti-PD-1 antibodies (Abs) are among the optimal adjuvant therapies for melanoma at high risk of recurrence, especially BRAF wild-type melanoma, but the anti-tumour effects of anti-PD-1 Abs in the adjuvant setting for acral melanoma have not been evaluated previously. The aim of this study was to analyse the efficacy and safety profiles of anti-PD-1 Ab monotherapy in the adjuvant setting in an Asian population including a high ratio of acral melanoma. The efficacy and safety profiles of anti-PD-1 Ab monotherapy in the adjuvant setting were retrospectively analysed in 78 Japanese patients with advanced melanoma, including 31 cases (40%) of acral melanoma. Overall relapse-free survival was 60.3% (47 of 78 cases, 95% confidence interval (CI) 49.2-70.4%), and 39.7% of patients (31 of 78 patients, 95% CI 29.6-50.8%) relapsed during the adjuvant PD-1 Ab treatment. Six cases (7.9%) discontinued the protocol due to serious adverse events. One case (1.3%) discontinued the protocol due to trauma. The relapse-free survival of acral melanoma was 25.8%, whereas that of high cumulative sun damage was 60.0%, and that of low cumulative sun damage was 57.1%. The acral type had a significantly lower 12-month relapse-free survival than other cutaneous types (p = 0.029). The acral type appeared to be an independent prognostic factor on multivariate analysis (p = 0.015). Adverse events due to anti-PD-1 antibody were observed in 37.1% overall. The results of this study suggest that anti-PD-1 Ab therapy in the adjuvant setting is less effective for acral melanoma than for other cutaneous types.

Management of Acral and Mucosal Melanoma: Medical Oncology Perspective

Acral and mucosal melanomas (MM) are rare subtypes of melanoma that are biologically and clinically distinct from cutaneous melanoma. Despite the progress in the treatment of cutaneous melanomas with the development of targeted and immune therapies, the therapeutic options for these less common subtypes remain limited. Difficulties in early diagnosis, the aggressive nature of the disease, and the frequently occult sites of origin have also contributed to the poor prognosis associated with acral and MM, with substantially worse long-term prognosis. The rarity of these subtypes has posed significant barriers to better understanding their biological features and investigating novel therapies. Consequently, establishing standardized treatment guidelines has been a challenge. In this review, we provide a brief overview of the current knowledge regarding acral and MM, focusing on their epidemiology, genetic backgrounds, and unique clinical characteristics. Further discussion centers around the management of primary and advanced disease and the role of emerging targeted and immune therapies for these subtypes, specifically focusing on issues relevant to medical oncologists.

Systematic review and meta-analysis of genomic alterations in acral melanoma

Acral melanoma (AM) tumors arise on the palms, soles, fingers, toes, and nailbeds. A comprehensive systematic meta-analysis of AM genomic aberrations has not been conducted to date. A literature review was carried out to identify studies sequencing AM. Whole-genome/exome data from 181 samples were identified. Targeted panel sequencing data from MSK-IMPACT were included as a validation cohort (n = 92), and studies using targeted hot spot sequencing were also collated for BRAF (n = 26 studies), NRAS (n = 21), and KIT (n = 32). Statistical analysis indicated BRAF, NRAS, PTEN, TYRP1, and KIT as significantly mutated genes. Frequent copy-number aberrations were also found for important cancer genes, such as CDKN2A, KIT, MDM2, CCND1, CDK4, and PAK1, among others. Mapping genomic alterations within the context of the hallmarks of cancer identified four components frequently altered, including (i) sustained proliferative signaling and (ii) evading growth suppression, (iii) genome instability and mutation, and (iv) enabling replicative immortality. This analysis provides the largest analysis of genomic aberrations in AM in the literature to date and highlights pathways that may be therapeutically targetable.

Survival differences in acral lentiginous melanoma according to socioeconomic status and race

BACKGROUND

Relationships of socioeconomic status (SES) and race to survival in acral lentiginous melanoma (ALM) are poorly characterized.

OBJECTIVE

To compare disease-specific survival in ALM across SES and race.

METHODS

Retrospective cohort study using the Surveillance, Epidemiology, and End Results database, 2000 to 2016.

RESULTS

We identified 2245 patients with a first ALM diagnosis. Five-year disease-specific survival was 77.8% (95% CI, 75.9%-79.9%). After adjustment, patients in the lowest and second-to-lowest SES quintile had 1.33 (95% CI, 0.90-1.96) and 1.42 (95% CI, 1.03-1.97) times the risk of death, respectively, compared to highest quintile patients. Hispanic White and Black patients had 1.48 (95% CI, 1.10-1.99) and 1.25 (95% CI, 0.88-1.79) times the risk of death, respectively, compared to non-Hispanic Whites. Hazard ratios for ALM-specific death decreased in Hispanic White and Black patients after adjusting for SES and American Joint Committee on Cancer stage at diagnosis.

LIMITATIONS

Treatments could not be evaluated. SES was measured at the level of the census tract and does not account for individual level factors.

CONCLUSION

Differences exist in ALM survival according to socioeconomic status and race. Differences in SES and American Joint Committee on Cancer stage at diagnosis contribute to survival disparities for Hispanic White and Black patients. Understanding factors driving survival disparities related to SES and race may improve ALM outcomes.

CD103+ T Lymphocyte Count Linked to the Thickness of Invasion on Acral Melanoma without E-Cadherin Involvement

Background

Acral melanoma (AM) is a malignancy that originates from melanocytes, located in an anatomical area without sun exposure, aggressive, resistant to chemotherapy, and quickly metastasize. The invasion capability of tumor cells is the main factor for metastasis in malignancy. E-cadherin is a marker of tumor progressivity that has an important role in the process of invasion. The responsibility of E-cadherin in the invasion process of AM is not well known. CD103 is an immune component found in the tumor microenvironment that contributes to melanoma progression control, whereas E-cadherin is the ligand for CD103.

Purpose

The objective of this research was to see if there was an association between E-cadherin and CD103 immunoexpression and the thickness of invasion in AM.

Materials and Methods

This is observational cross-sectional research. Formalin-fixed paraffin-embedded (FFPE) acral melanoma tissue samples were collected during 2014–2020 at the Department of Anatomic Pathology, Dr. Hasan Sadikin Hospital, Bandung. A total of 40 samples were collected, including 20 cases of invasive melanoma less than 4 mm thickness and 20 cases of invasive melanoma greater than 4 mm thickness. All samples were immunostained with E-cadherin and CD103. Chi-Square test was used to examine the association concerning E-cadherin and CD103 with the thickness of invasion, respectively. The p-value of 0.05 was chosen as the significance level.

Results

This study showed an insignificant association between E-cadherin immunoexpression and the thickness of invasion on AM (p = 0.4272). CD103 immunoexpression had a significant association with the thickness of invasion on AM (p = 0.0001).

Conclusion

The findings revealed that CD103 in AM is associated with the thickness of invasion, and it may play important functions throughout the invasion process despite the uninvolvement of E-cadherin.

Volar location and degree of pigmentation are associated with poor survival and first metastasis pattern in acral melanoma

The risk factors affecting acral melanoma metastasis and prognosis remain unclear. The study included 168 patients with invasive acral melanoma who were followed for ≥3 years. We evaluated patient demographics, stages, clinicopathological features, anatomic site of melanoma including nail versus volar surface, and degree of melanoma pigmentations, sentinel lymph node biopsy results, and the first metastasis sites. Of the 168 patients (mean age 64.5 years; 52.4% male), 43 (25.6%) had invasive melanoma without metastasis, 113 (67.3%) had invasive melanoma with a first lymph node metastasis, and 12 (7.1%) had invasive melanoma with invasive melanoma with a first distant metastasis. Advanced T stage, high mitotic rate, ulceration, and the degree of pigmentation were significant risk factors for metastasis. Amelanotic and mild pigmentation of acral melanoma was associated with first distant metastasis, whereas heavy pigmentation was associated with first lymph node metastasis. Advanced TNM stages, high mitotic rate, volar location (hazard ratio = 2.24, 95% confidence interval 1.18-4.26), and low-pigmentation (hazard ratio = 2.02, 95% confidence interval 1.17-3.49) were associated with melanoma-specific mortality.

More than just acral melanoma: the controversies of defining the disease

Acral melanoma (AM) is a malignant cutaneous melanocytic tumour specifically located on the palms, soles, and nail apparatus, which are areas of glabrous (hairless) skin. Acral lentiginous melanoma, a subtype of AM, represents a histopathological subtype diagnosis of cutaneous melanoma with unique morphological and structural features. Despite clear definitions, the misuse of these terms and the inconsistency in reporting the histopathological features of AM cases have become a major obstacle to the study of the disease. In this review, we discuss the epidemiology, histopathological features, prognosis, and genetic profile of AM, highlighting the differences observed when histopathological subtypes are considered. The increasing global effort to characterise AM cases from ethnically diverse populations would benefit greatly from a more consistent classification of the disease.

Establishment of cultured primary acral melanoma cells and animal models for Chinese patients

Acral melanoma is the major subtype of melanoma in Chinese patients. However, a majority of current studies focused on non-acral melanoma. Most immortalized melanoma cell lines and primary cells were not from acral melanoma. Besides, there are rarely reports about methods for establishing primary acral melanoma cell cultures and related animal models. Here, we present four new human primary acral melanoma cell lines. To determine the mutational profile of the established primary melanoma cells for future targeted use, we performed exome sequencing. We next examined cell proliferation of the primary acral melanoma cells by colony-formation assays and CCK8 assay. We also evaluated the proliferative and metastatic potential of XYAM-4 in vivo. We report a detailed protocol for establishing cultured primary acral melanoma cells for Chinese patients and related animal models. We also summarize the features in our acral melanoma cell lines and the existing acral melanoma cell lines. This will provide an effective research tool for research on drug responses and individualized treatment for Chinese patients and comparative studies of melanomas between western and Chinese populations.

[Determination of the Subclonal Tumor Structure in Childhood Acute Myeloid Leukemia and Acral Melanoma by Next-Generation Sequencing]

Intratumoral heterogeneity and clonal variability are among the central problems of clinical oncology, leading to resistance to therapy, relapse, and metastasis. High-throughput sequencing of the tumor exome makes it possible to investigate the subclonal tumor organization. Target panel, clinical exome, and complete exome sequencing data were compared in tumors with different mutational burden, acute myeloid leukemia (AML) in children and acral melanoma. Targeted sequencing of AML samples detected more than one potential driver mutation in the signaling pathway genes KIT, NRAS, KRAS, CBL, and FLT3 in one patient, reflecting the complex clonal structure of the tumor substrate. Clusters of mutant alleles corresponding to different populations of leukemic cells in a sample were isolated based on exome sequencing data from the same AML patients. A comparison of the mutation profile for a primary AML sample and samples obtained in remission and relapse made it possible to trace the dynamic changes in the clonal composition of the tumor. The subclonal tumor structure was investigated in an acral melanoma case as an example. Mutant alleles present in the sample with close frequencies were clustered using the SciClone and ClonEvol packages. The results were used to predict the intratumoral clonal composition and to assume a clonal evolution model, which described the changes in the clonal composition of the tumor during metastasis, including the appearance of new mutations that might be associated with further disease progression. The approach used in the work is suitable for identifying the mutations that cause the formation of new tumor clones, which may have a proliferative advantage, in particular, in conditions of antitumor therapy.

Overall Survival of Patients With Unresectable or Metastatic BRAF V600-Mutant Acral/Cutaneous Melanoma Administered Dabrafenib Plus Trametinib: Long-Term Follow-Up of a Multicenter, Single-Arm Phase IIa Trial

Objectives

To examine the long-term survival outcome of dabrafenib in combination with trametinib in Chinese patients with unresectable or metastatic acral/cutaneous melanoma with BRAF-V600 mutation and to explore potential predictors of effectiveness.

Methods

This was a long-term follow-up of Chinese patients with unresectable or metastatic BRAF V600-mutant acral/cutaneous melanoma administered dabrafenib (150 mg twice daily) plus trametinib (2 mg once daily) in an open-label, multicenter, single-arm, phase IIa study (NCT02083354). Efficacy endpoints included objective response rate (ORR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS). The impacts of baseline characteristics on PFS and OS were analyzed.

Results

A total of sixty patients were included. The median age was 48 years, and 24 patients (40.0%) were male. Totally 12 individuals (20.0%) had acral melanoma, and 45 (75.0%) had failed previous systemic therapy. Up to July 2020, the median duration of follow-up was 37.0 (95% confidence interval [CI] 29.1-44.9) months. The updated ORR was 71.7% (95%CI 60.3%-83.1%). The 3-year OS rate was 28.8% (95%CI 19.1-43.6%) in the overall population, and 35.7% (95%CI 15.5–82.4%) in acral melanoma patients. The median DOR was 7.5 months (95%CI 4.5 to 10.5). Baseline normal lactic dehydrogenase (LDH), metastatic organ sites<3 and complete response to combination therapy with dabrafenib plus trametinib were associated with improved PFS and OS.

Conclusion

Dabrafenib combined with trametinib confer long-term survival in Chinese patients with BRAF V600-mutant, unresectable or metastatic acral/cutaneous melanoma.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT02083354, identifier NCT02083354.

Adjuvant PD-1 inhibitor versus high-dose interferon α-2b for Chinese patients with cutaneous and acral melanoma: A retrospective cohort analysis

The clinical efficacy of PD-1 inhibitors as an adjuvant treatment for Asian melanoma patients has not yet been determined. This retrospective study analyzed the clinical data of 90 Chinese patients with completely resected, stage III cutaneous or acral melanoma who received either adjuvant PD-1 inhibitor or high-dose interferon α-2b (HDI). Anti-PD-1 treatment resulted in significantly longer RFS and DMFS than HDI in cutaneous melanoma patients, with hazard ratios (HRs) (anti-PD-1 versus HDI) of 0.402 (95% CI, 0.183-0.886) and 0.324 (95%CI, 0.122 to 0.861) for RFS and DMFS, respectively. However, adjuvant anti-PD-1 treatment had no advantage over HDI in acral melanoma patients with HRs (anti-PD-1 versus HDI) of 1.204 (95% CI, 0.521 to 2.781) and 1.968(95% CI, 0.744-5.209) for RFS and DMFS, respectively. Adjuvant anti-PD-1 treatment yielded a significantly better prognosis than HDI in Chinese patients with stage IIIB/C cutaneous melanoma, but a significant difference was not observed in those with acral melanoma.

Immunotherapy in Acral and Mucosal Melanoma: Current Status and Future Directions

Acral and mucosal melanomas are extremely rare in Caucasians; however, they are the predominant melanoma subtypes in Asians and other non-Caucasian populations. Acral and mucosal melanomas share many clinicopathological features, including aggressive phenotypes, similar genetic landscapes, and grim prognoses. In spite of advances in melanoma management, patients with acral and mucosal melanomas show limited benefit from current therapies. The rarity of these subtypes of melanoma is a significant factor contributing to the poor understanding of these pathological subtypes and the lack of effective interventions. Furthermore, the mechanisms contributing to disparities between different types of melanoma remain largely unclear. Herein, we comprehensively review current knowledge on the clinicopathological characteristics and mutational landscapes of acral and mucosal melanomas, as well as providing an overview of current therapies for patients with these aggressive melanoma subtypes, focusing on available immunotherapeutic interventions. We also discuss pathological differences between different melanoma subtypes and summarize current knowledge on melanoma disparities between Asians and Caucasians. Finally, we discuss emerging immunotherapeutic strategies for the treatment of acral and mucosal melanomas, focusing on combination therapies with immune checkpoint inhibitors. Unraveling the unique features of acral and mucosal melanomas is key for their early diagnosis and for the development of effective therapies.

Identification of genetic mutations related to invasion and metastasis of acral melanoma via whole-exome sequencing

Many studies have analyzed the genes related to melanoma. However, only a limited number of studies have been conducted to identify the genes that are involved in the invasion and metastasis of acral melanoma (AM). Here, we attempted to investigate the genetic mutations associated with invasion and metastasis of AM. We analyzed five multi-regional samples of primary and metastatic AM and histologically normal tissue adjacent to the tumor (NAT) in two AM patients by whole-exome sequencing (WES). We identified single nucleotide variations and small indels present in tissue samples but not in saliva. We compared the sequencing results of superficial and deep lesions and primary and metastatic lesions of AM. We identified significantly deleterious mutations (SDM) that are likely to be related to invasion and metastasis of AM, respectively. SDM such as SKA3, MAST4, CNNM1, KIAA1549L, and SLC26A10 were found only in the deep lesion, but not in the superficial lesion. SDM present only in the metastatic lesion were ANO1, CPEB1, EP300, INADL, MAP1B, MAP7D1, MARCH6, NETO1, PRKCE, SBK1, TNRC6A, USP13, WDR74, and ZNF827. In conclusion, we applied multi-region WES to investigate possible pathogenic mutations related to invasion and metastasis in AM. Several genes including CNNM1, USP13, ZNF827, WDR74, CPEB1, and EP300 might be related to invasion and metastasis of AM. This study might facilitate the exploration of the evolutionary pathogenesis of advanced AM.

The Molecular Landscape of Primary Acral Melanoma: A Multicenter Study of the Italian Melanoma Intergroup (IMI)

Acral melanoma (AM) is a rare and aggressive subtype of melanoma affecting the palms, soles, and nail apparatus with similar incidence among different ethnicities. AM is unrelated to ultraviolet radiation and has a low mutation burden but frequent chromosomal rearrangements and gene amplifications. Next generation sequencing of 33 genes and somatic copy number variation (CNV) analysis with genome-wide single nucleotide polymorphism arrays were performed in order to molecularly characterize 48 primary AMs of Italian patients in association with clinicopathological and prognostic features. BRAF was the most commonly mutated gene, followed by NRAS and TP53, whereas TERT promoter, KIT, and ARID1A were less frequently mutated. Gains and losses were recurrently found in the 1q, 6p, 7, 8q, 20 and 22 chromosomes involving PREX2, RAC1, KMT2C, BRAF, CCND1, TERT, and AKT3 genes, and in the 6q, 9, 10, 11q and 16q chromosomes including CDKN2A, PTEN, and ADAMTS18 genes, respectively. This study confirmed the variety of gene mutations and the high load of CNV in primary AM. Some genomic alterations were associated with histologic prognostic features. BRAF mutations, found with a higher rate than previously reported, correlated with a low Breslow thickness, low mitotic count, low CNV of the AMs, and with early-stage of disease.

Clinical Significance of Tumor Microenvironment in Acral Melanoma: A Large Single-Institution Study of Caucasians

Background: The presence of tumor-infiltrating lymphocytes (TILs) in many studies is associated with a better prognosis in melanoma patients. Programmed death-ligand 1 (PD-L1) expression has a significant value in predicting several cancers, but its role in melanoma remains ambiguous. The study aims to report a comprehensive analysis of TILs characteristics and their impact on survival in primary acral melanoma (AM). Methods: Clinical and pathological features and survival outcomes were investigated in 70 patients with AM. Immunohistochemical quantitative analysis of TILs, including expression of CD4, CD8, FOXP3, PD-1, and PD-L1, on melanoma cells was performed. Results: Kaplan-Meier analysis showed significant differences in overall survival (OS) for CD4+ (p = 0.021), CD8+ (p = 0.037), FOXP3+ (p = 0.007), and TILs density (p = 0.043). In univariate analysis of immunohistochemical features, FOXP3, CD4, CD8, PD-1, and Melanoma Institute of Australia (MIA) grading TILs (grade, density, and distribution) were correlated with survival. The higher density of FOXP3-positive cells was an independent factor associated with better survival. Conclusions: High TILs content (classed as brisk Clark scale and marked/diffuse TILs MIA grade) regardless of its immunophenotype was associated with better survival outcomes in AM. PD-L1 expression on tumor cells did not influence OS and was independent of clinical and pathological characteristics. We demonstrated that TILs are significant biomarkers in sentinel lymph node status prediction.

The efficacy of anti-programmed cell death protein 1 therapy among patients with metastatic acral and metastatic mucosal melanoma

Background

Anti‐programmed cell death protein 1 (PD‐1) antibodies are a standard treatment for metastatic melanoma patients. However, the understanding of the efficacy of anti‐PD‐1 for acral melanoma (AM) and mucosal melanoma (MM) is limited as these subtypes are relatively rare compared to cutaneous melanoma (CM).

Methods

This single institution, retrospective cohort study included patients with advanced AM and MM who underwent anti‐PD‐1 therapy for metastatic melanoma between 2012 and 2018. Objective responses were determined using the investigator‐assessed Response Evaluation Criteria in Solid Tumors version 1.1. Progression‐free survival (PFS) and overall survival (OS) were assessed using the Kaplan–Meier method. A Cox regression analysis was performed to identify the factors associated with survival outcomes.

Results

Ninety‐seven patients were identified, 38 (39%) with AM and 59 (61%) with MM. The objective response rates (ORRs) were 21.0% and 15.2% in patients with AM and MM, respectively. The median PFS and OS were 3.6 and 25.7 months for AM patients, and 3.0 and 20.1 months for MM patients, respectively. Elevated serum lactate dehydrogenase (LDH) (AM: hazard ratio [HR], 0.22; 95% confidence interval [CI], 0.06–0.87; p = 0.03, MM: HR, 0.20; 95% CI, 0.08–0.53; p = 0.001) was significantly associated with shorter OS for both subtypes.

Conclusions

The ORR, PFS, and OS with anti‐PD‐1 therapy were poor in patients with AM and MM compared to those previously reported clinical trials for nonacral CM. High serum LDH was associated with significantly shorter OS.

High Expression of COX-2 Associated with the Depth of Invasion on Acral Melanoma by Increasing TGF-β1

Introduction

Acral melanoma (AM) has a poor prognosis since it is easily metastatic and resistant to chemo and immunotherapy. Cyclooxygenase-2 (COX-2) is an enzyme that plays a role in the carcinogenesis process. The increased expression of COX-2 has an impact on increasing levels of Myeloid-Derived Suppressor Cell (MDSC), which is a key regulator of immune. The increase in MDSC produces Transforming Growth Factor β1 (TGF-β1), which will suppress Natural Killer (NK) cells and Dendritic Cells (DC) function so that tumor cells are spared from the immune systems and are easier to invade surrounding tissues.

Purpose

This study aimed to determine the role of COX-2 and TGF-β1 on the depth of invasion on AM.

Materials and Methods

This study was a cross-sectional observational study on 40 paraffin blocks of AM cases during 2014-2019 in the Department of Pathology Anatomy, Faculty of Medicine, Dr. Hasan Sadikin General Hospital, Bandung. The depth of invasion of all samples was measured by dotSlide imaging software and the immunohistochemical staining of COX-2 and TGF-β1 was performed. The association between COX-2 and TGF-β1 expression and AM depth of invasion were analyzed using Mann Whitney.

Results

The result showed a significant association between COX-2 and TGF-β1 expression and depth of invasion on AM. COX-2 expression had a significant association with TGF-β1 expression (0.0001). Through multivariate analysis, it was found that COX-2 had the greatest association with the depth of invasion (p=0.0001).

Conclusion

The findings showed that increasing expression of COX-2 in AM is associated with the depth of invasion by increasing TGF-β1 and it might play important roles during the invasion process of AM.

Talon Noir in a Young Baseball Player: A Case Report

When evaluating pediatric patients with hyperpigmented lesions on the plantar aspect of the feet, the differential diagnosis should include talon noir, acral melanoma, and verruca with thrombosis. Talon noir are asymptomatic brown-black pigmented macules formed by intraepidermal hemorrhages of the feet caused by shear-force injury. Spontaneous resolution of talon noir typically occurs within 2-3 weeks. Clinicians should ensure that their patients who participate in sports have appropriately fitting shoes, which may prevent these lesions from occurring. This case report highlights a unique case of talon noir occurring in a young baseball player with an atypical distribution of plantar macules.

Preoperative Screening CT and PET/CT Scanning for Acral Melanoma: Is it Necessary?

The efficacy of preoperative imaging for acral melanoma (AM) has not been fully evaluated. We examined the accuracy of imaging modalities in the detection of nodal and distant metastases in patients with AM. A retrospective review of 109 patients with AM was performed. All patients had no clinical signs suggestive of distant metastases, and underwent preoperative screening computed tomography (CT) and positron emission tomography (PET)/CT scans. Of 100 patients without lymphadenopathy, 17 patients were suspected of having nodal metastasis in CT and PET/CT, but only two of them were confirmed on histopathological analysis. On the other hand, 12 out of 83 negatively imaged patients showed histopathological signs of nodal metastasis; thus, the sensitivity and specificity of nodal detection were 14.3% and 82.6%, respectively. Regard to the detection of distant metastases, four patients were suspected of having metastasis, but this was later ruled out. The remaining 96 negatively imaged patients were confirmed to have no metastasis at the time of CT and PET/CT by the follow-up. In contrast, distant metastases were found by CT and PET/CT in four of nine patients (44.4%) with lymphadenopathy. Routine preoperative CT and PET/CT for AM patients without lymphadenopathy may not be warranted because of low sensitivity and specificity, but it can be considered for those with lymphadenopathy.

Sentinel lymph node biopsy in acral melanoma: A Korean single-center experience with 107 patients (2006-2018)

BACKGROUND

Sentinel lymph node biopsy (SLNB) of primary cutaneous melanoma as an important staging method has not been popularly undertaken in Korea and only a few studies with small patient numbers have been published.

AIM

We examined the clinical feasibility and overall outcomes of SLNB in acral melanoma (AM) of Korean in Kyungpook National University Hospital (KNUH) over the past 13 years.

METHODS

SLNB in AM patients during 2006-2018 were analyzed retrospectively for sentinel lymph node (SLN) harvesting rate, positivity rate, positivity-relevant overall survival (OS) and disease-free survival (DFS), and its side effects.

RESULTS

A total of 109 AM patients who underwent SLNB were enrolled. Harvested nodes were identified from 107 patients and SLN harvesting rate was 98.2%. The mean Breslow thickness (±standard deviation) was 3.38 ± 3.03 mm, and the proportion of ulcerated melanomas was 64%. Twenty-two (20.6%) had a tumor-positive SLN and, among them, 82% (18/22) underwent immediate complete lymph node dissection (CLND). The metastasis-positive nodal basin after CLND was detected in 16.7% of cases (3/18). Tumor-negative SLN cohorts showed significantly better OS and DFS than tumor-positive ones (P = 0.006 and P < 0.001 for each). Two side effects, one seroma and one lymphocele, were observed without major sequelae.

CONCLUSION

SLNB, crucial management of melanoma, proved its efficacy to predict patients' prognosis and could be performed successfully and safely in Korean AM patients by interdisciplinary cooperation between dermatology and other surgical departments. SLN(-) showed significantly better OS and DFS than SLN(+). Significant risk factors for DFS were Breslow thickness, the presence of ulceration and the presence of SLN metastasis. SLNB should be encouraged in order to stage melanoma accurately and direct the proper management in Korean AM.

Immunotherapy for advanced melanoma: current situation in Japan

Treatment with immune checkpoint inhibitors provides long-term survival for patients with advanced melanoma. Improvements in the overall survival of advanced melanoma patients have been achieved with anti-PD-1 monotherapy and anti-PD-1+ CTLA4 combination therapy, but there are still many issues to resolve. Acral, mucosal and uveal melanoma have been less responsive to immune checkpoint inhibitors than cutaneous melanoma. For patients who have achieved a good response, it is still not known how long the anti-PD-1 therapy should be administered. Moreover, there is limited treatment for patients who relapse during or after adjuvant anti-PD-1 therapy. Here, we review the current evidence regarding the clinical effects of immunotherapy for advanced melanoma. Moreover, we review previous studies of acral, mucosal and uveal melanoma, and we discuss the recent findings regarding durable response after the cessation of anti-PD-1 therapy, and treatment options for recurrence after adjuvant therapy.

Novel LRRFIP2-RAF1 fusion identified in an acral melanoma: A review of the literature on melanocytic proliferations with RAF1 fusions and the potential therapeutic implications

A small subset of cutaneous melanomas harbor oncogenic gene fusions, which could potentially serve as therapeutic targets for patients with advanced disease as novel therapies are developed. Fusions involving RAF1 are exceedingly rare in melanocytic neoplasms, occurring in less than 1% of melanomas, and usually arise in tumors that are wild type for BRAF, NRAS, and NF1. We describe herein a case of acral melanoma with two satellite metastases and sentinel lymph node involvement. The melanoma had a concomitant KIT variant and LRRFIP2-RAF1 fusion. This constellation of molecular findings has not been reported previously in melanoma. We review the existing literature on melanocytic neoplasms with RAF1 fusions and discuss the potential clinical implications of this genetic event.