Immune checkpoint inhibitor-based therapy for advanced acral and mucosal melanoma.

Acral melanoma (AM) and mucosal melanomas (MM) are rare clinical subtypes of melanoma. AM and MM are etiologically, biologically, and molecularly distinct from cutaneous melanoma (CM). Despite the recent development of immune checkpoint inhibitors (ICIs) for the treatment of advanced CMs, the true therapeutic efficacy of ICIs for these rare subtypes remains unclear. Since these subtypes are rare, especially in the Caucasian population, their biological features and corresponding novel therapies are underexplored than those of CM. Even in the larger phase III clinical trials for ICIs, the sample size of patients with AM and MM is limited. Consequently, establishment of standard of care for advanced AM and MM has been challenging. This review covers current update and overview on clinical efficacy of ICIs and ICI-based therapy for advanced AM and MM, based mainly on the reported clinical trials, prospective observational studies, and retrospective studies, to provide a better understanding of the current landscape of this field. In addition, we discuss the future direction of treatment for those rare clinical subtypes, focusing on issues relevant to dermatology and medical oncology.

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

AIMS: Subungual melanoma (SUM) is increasingly being treated with conservative surgery. Consequently, the evaluation of the 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 the surrounding skin. We examined whether PReferentially expressed Antigen in MElanoma (PRAME) immunohistochemistry and fluorescence in situ hybridisation (FISH) labelling 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 the examined cases were diffusely positive, this was found for only 9.4% of hyperplastic melanocyte cases. Four-coloured FISH using whole-slide digital imaging was used to analyse 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 tumour 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.

Favorable efficacy of S-1 treatment for locoregionally advanced cutaneous squamous cell carcinoma in the head and neck region.

Cutaneous squamous cell carcinoma is usually treated with surgery; however, locoregionally advanced cutaneous squamous cell carcinoma can be difficult to resect. Although recent guidelines from Western countries recommend using anti-programmed cell death protein 1 (PD-1) antibodies, including cemiplimab and pembrolizumab, there are no approved anti-PD-1 antibodies for locoregional cutaneous squamous cell carcinoma in Asian countries. S-1 is an oral drug with a low incidence of severe toxicity that can be used for head and neck cancers, including head and neck locoregional cutaneous squamous cell carcinoma, in Japan. We retrospectively evaluated patients with head and neck locoregional cutaneous squamous cell carcinoma treated with S-1 at two Japanese institutions (2008-2022). The initial dosage was determined by the body surface area (<1.25 m2 : 80 mg/day, 1.25-1.5 m2 : 100 mg/day, ≥1.5 m2: 120 mg/day) for 28 consecutive days. The outcome measures were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Fourteen patients were included. The ORR was 78%, and the complete response (CR) rate was 64.3%. The median PFS and OS were not reached (NR) (95% confidence interval [CI], 5.9 months-NR) and NR (95% CI, 13.8 months-NR), respectively. The 12-month PFS and OS rates were 51% and 85%, respectively. Six of the nine patients who achieved CR showed no recurrence during the follow-up period (median follow-up, 24.7 months). After CR, three patients experienced recurrence. Among these, two resumed S-1 treatment and subsequently underwent salvage surgery, resulting in a sustained absence of recurrence. One patient developed lung metastasis and died, although S-1 therapy was resumed. Only one patient (7.1%) developed grade 3 anemia. S-1 showed favorable efficacy and low toxicity in patients with head and neck locoregionally advanced cutaneous squamous cell carcinoma. S-1 may be a good alternative to the anti-PD-1 antibody for treating head and neck locoregionally advanced squamous cell carcinoma.

Application of fluorescence in situ hybridization in distinguishing acral melanoma in situ from acral junctional melanocytic nevus on the volar skin in Japanese patients.

Four-colored fluorescence in situ hybridization (FISH) is an ancillary diagnostic tool for melanoma. However, most studies that have investigated the usefulness of FISH primarily focused on advanced melanomas. The aim of the current study was to evaluate the effectiveness of FISH in distinguishing acral melanoma (AM) in situ from benign acral junctional nevus (AJN), two types of lesions that are difficult to differentiate via traditional clinical means. The authors investigated the usefulness of FISH in 91 acral melanocytic lesions, including 50 lesions with diagnostic discrepancies between dermoscopic and pathologic approaches or difficulty diagnosing between AM in situ and AJN, on the volar skin of Japanese patients. The authors classified the lesions based on the diagnosis of dermatologists and pathologists into four groups: (I) lesions with a unanimous diagnosis by dermatologists and pathologists as AM in situ or AJN (n = 41); (II) lesions with a unanimous diagnosis by dermatologists only as AM in situ or AJN (n = 21); (III) lesions with a unanimous diagnosis by pathologists only as AM in situ or AJN (n = 15); and (IV) all other lesions (n = 14). The dermatologists diagnosed the lesions by clinical and dermoscopic photographs alone, while the pathologists diagnosed the lesions by microscopy of hematoxylin and eosin-stained slides alone. In group I (AM in situ [n = 20] and AJN [n = 21]), four-colored FISH demonstrated 90% sensitivity and 81% specificity in distinguishing AM in situ from AJN. There was a significant correlation between the FISH results and the unanimous diagnoses by pathologists alone (p = 0.03) in group III. However, FISH results were not significantly correlated with the unanimous diagnoses by dermatologists alone (p = 0.33) in group II. In conclusion, the four-colored FISH probe kit was useful in distinguishing between AM in situ and AJN and may be an ancillary method when pathologists who are not experts of dermatopathology diagnose melanocytic lesions.

Comparison of surgical morbidities between LigaSure™ and conventional techniques in inguinal or ilioinguinal lymph node dissection for skin cancer: A single center retrospective study.

Skin cancer patients with clinical nodal disease or whose positive sentinel nodes had great tumor burden remain candidates for regional lymph node dissections. Among these patients, inguinal or ilioinguinal lymph node dissection is frequently required in clinical practice, which is associated with significant postoperative morbidity-including lymphatic leakage. The aim of this retrospective study was to evaluate the efficacy of LigaSure™, an electrothermal bipolar vessel sealing system, in reducing lymphatic leakage in inguinal or ilioinguinal lymph node dissection. In total, 58 patients who received inguinal or ilioinguinal lymph node dissection (conventional group, 48; LigaSure™ group, 10) and shared similar characteristics were included in this study. Lymphatic leakage after drain removal was significantly lower in the LigaSure™ group than that in the conventional group (present ratio, 0% vs. 37%; p = 0.02). The daily lymphatic drainage volume also tended to be lower in the LigaSure™ than that in the conventional group, with significant differences on postoperative day 1 (p = 0.02). Other perioperative outcomes including the operating time, intraoperative blood loss, time to drain removal, duration of hospital stay, flap necrosis, and wound infection showed no significant differences between the two groups. The use of the LigaSure™ in inguinal or ilioinguinal lymph node dissection for the treatment of skin cancer could reduce the incidence of postoperative lymphatic leakage after drain removal.