Effects of temozolomide on tumor mutation burden and microsatellite instability in melanoma cells.

The efficacy of combination therapy with an immune checkpoint inhibitor (ICI) and cytotoxic chemotherapeutic agents has been investigated in cancer, including melanoma. Before ICIs were introduced, dacarbazine or temozolomide (TMZ) were used to treat melanoma. Several studies using glioma or colorectal cancer cells showed that TMZ can increase the tumor mutation burden (TMB) and induce mismatch repair (MMR) deficiency associated with microsatellite instability (MSI). These could increase immunoreactivity to an ICI, but this has not been evaluated in melanoma cells. We investigated the effects of TMZ on MSI status and TMB in melanoma cells. To evaluate the TMB, we performed whole-exome sequencing using genomic DNA from the human melanoma cell lines Mel18, A375, WM266-4, G361, and TXM18 before and after TMZ treatment. Polymerase chain reaction amplification of five mononucleotide repeat markers, BAT25, BAT26, NR21, NR24, and MONO27, was performed, and we analyzed changes in the MSI status. In all cell lines, the TMB was increased after TMZ treatment (the change amount of TMB with ≤ 5% variant allele frequency [VAF] was 18.0-38.3 mutations per megabase) even in the condition without obvious cytological damage. MSI after TMZ treatment was not observed in any cells. TMZ increased TMB but did not change MSI status in melanoma cells.

Difference in immunohistochemical findings among anti-PD-L1 antibodies and their relationships with CD4+ and CD8+ T cells in Japanese melanoma patients.

BACKGROUND: The immunohistochemical evaluation of programmed death ligand 1 (PD-L1) is important for selecting treatments. Several antibodies are available for such evaluations, but data regarding the differences in the antibodies' positivity are limited in melanoma, particularly the acral and mucosal types. We investigated the differences in melanoma tissues' PD-L1 expression among the commonly used PD-L1 antibodies and then evaluated the relationship between PD-L1+ tumor cells and tumor-infiltrating lymphocytes (TILs). PATIENTS AND METHODS: We examined 56 primary lesions and 8 metastatic lymph node samples from 56 Japanese patients with melanoma (28 acral melanoma, 8 mucosal melanoma, 18 cutaneous melanoma, 2 unknown). Immunohistochemical staining was performed using three primary antibodies against PD-L1 (E1L3N, SP142, and 28-8). PD-L1-positive staining in tumor cells was defined as ≥ 1% expression. RESULTS: The positive rates were 25.0% for 28-8, 34.0% for E1L3N, and 34.0% for SP142 in 64 samples. The positive rates of acral melanoma were 10.7% for 28-8, 21.4% for E1L3N, and 21.4% for SP142. The positive rate of mucosal melanoma for which all three antibodies reacted was 12.5%. The positive rates of cutaneous melanoma were 55.6% for 28-8, 66.7% for E1L3N, and 66.7% for SP142. Significant relationships were observed among the PD-L1+ tumor cells, CD4+ TILs, and CD8+ TILs (p < 0.001). CONCLUSION: The staining results by E1L3N, SP142, and 28-8 antibodies were within the allowable range, although the positive rates by E1L3N and P142 were slightly higher than that of 28-8. CD4+ TILs and CD8+ TILs were quantitatively correlated with PD-L1-positive tumor cells.

Usefulness of neuron-specific enolase as a serum marker of metastatic melanoma.

Treatment strategies for advanced melanoma are dramatically changing, due to immune-checkpoint inhibitors and BRAF/MEK inhibitors. Nevertheless, reliable serum markers for evaluation of treatment responses and the outcome are still limited. Some previous reports suggested that serum neuron-specific enolase (sNSE) may be a useful marker for melanoma; however, its usefulness is controversial. Moreover, NSE has not been examined in vitro by using melanoma cell lines. We retrospectively evaluated sNSE and serum lactate dehydrogenase (sLDH) levels at the initial diagnosis and during therapy in 33 melanoma patients of various stages. We analyzed the NSE concentrations in cell lysates and supernatants from melanoma cell lines by enzyme-linked immunosorbent assay. The median sNSE was significantly higher in stage IV patients compared with stages I/II and III (16.3, 12.7 and 12.1 ng/mL, respectively). sNSE was elevated in 20% (2/10) of stage III and 61.1% (11/18) of stage IV patients but not in stages I/II. sNSE and sLDH tended to correspond to the total tumor volume (P = 0.48 and 0.58; 95% confidence intervals, 0.005-0172 and 0.776-0.836, respectively). The coincidence rate of sNSE and sLDH in stage IV at the initial diagnosis was 11 of 18 (61.1%). Of the remaining patients, elevated sNSE but not sLDH was observed in five patients (27.8%) and elevated sLDH but not sNSE was observed in two (11.1%). Four of the five patients showing elevated sNSE and normal sLDH were of the mucosal type. NSE was detected in both supernatant and cell lysate of all four melanoma cell lines (0.30-237.32 ng/mL and 137-483.04 ng/mg, respectively). Two cell lines with a high supernatant NSE level contained many dead cells in the supernatant. The combination of sNSE and sLDH could contribute to the early detection of distant metastasis and disease condition evaluations for advanced melanoma patients.

Association between PD-L1 expression and lymph node metastasis in cutaneous squamous cell carcinoma.

AIM: To clarify the relationship between programmed cell death ligand 1 (PD-L1) expression in cutaneous squamous cell carcinoma (cSCC) and clinicopathological variables. METHODS: We examined PD-L1 expression in tumor cells (TCs) and tumor infiltrating immune cells (ICs) in 46 cases of cSCC by immunohistochemistry. In each case, we employed two methods-intensity and proportion scores-to evaluate PD-L1 expression in TCs. For the evaluation of PD-L1 expression in ICs, only the proportion score was used. Association between PD-L1 expression and clinicopathological variables was analyzed using Fisher's exact test. RESULTS: High intensity scores in TCs were observed in 18 of the 46 cases (39.1%) and low intensity scores were observed in 28 cases (60.9%). Applying the proportions, using cut-off values of ≥1% and 50%, positive scores in TCs were observed in 36 (78.3%) and 20 cases (43.5%), respectively. PD-L1-positive ICs were observed in 29 (63%) and seven cases (15.2%), using cut-off values of ≥1% and 10%, respectively. The high intensity scores in TCs correlated with lymph node metastasis (P = 0.008) and female gender (P = 0.017), although positive proportions in TCs or ICs were not significantly related to lymph node metastasis. A multivariate analysis showed that high intensity of PD-L1 expression in TCs was an independent risk factor for lymph node metastasis. CONCLUSIONS: The results suggested that high intensity of PD-L1 expression in TCs is associated with lymph node metastasis in cSCC.

Efficacy of combined radiotherapy and anti-programmed death 1 therapy in acral and mucosal melanoma.

Some studies showed that clinical response to immune check point inhibitors is lower in acral and mucosal melanoma than in cutaneous melanoma. Although the synergistic effect of radiotherapy (RT) and ipilimumab has been reported in patients with brain metastasis, the efficacy of combined RT and anti-programmed death 1 (PD-1) therapy for acral and mucosal melanoma is unclear. The present study aimed to evaluate the efficacy of combined RT and anti-PD-1 therapy for acral and mucosal melanoma. We retrospectively analyzed patients with acral or mucosal melanoma who were treated with anti-PD-1 and RT at Sapporo Medical University Hospital. In 10 patients (acral, 3; mucosal, 7), the response rate (RR) and the disease control rate (DCR) were 40% and 60%, respectively. As regards mucosal melanoma, four of the seven patients had achieved complete response + partial response, and three had progressive disease (RR = 57.1%). Meanwhile, two of the three patients with acral melanoma had stable disease and one had progressive disease (RR and DCR were 0% and 66.6%, respectively). Except for the patients treated with palliative RT for bone metastasis in the present study, the RR was 50% (4/8 patients), and the DCR was 75% (6/8 patients). Vitiligo developed after RT in five (50%) patients at a median duration of 2 months after RT. The clinical response and the high occurrence of vitiligo suggest that the combination of RT and anti-PD-1 therapy could be effective in some patients with mucosal melanoma.

Successful TS-1 monotherapy as the second-line treatment for advanced extramammary Paget's disease: A report of two cases.

There is no standard chemotherapeutic treatment for advanced extramammary Paget's disease, though the effectiveness of some chemotherapy regimens, including docetaxel, has been reported. In this report, we report that TS-1 monotherapy was effective in two patients with advanced extramammary Paget's disease after docetaxel treatment failure. TS-1 monotherapy may be useful as the second-line treatment for patients with advanced extramammary Paget's disease.

Dermoscopic features distinctive for extraocular sebaceous carcinoma.

We examined dermoscopic features of three cases of extraocular sebaceous carcinoma and reviewed the literatures. The yellowish structures, polymorphous vessels and ulceration were common findings in our cases and all cases of the previous reports. The appearance of whitish-pink areas has not been described previously. Our results suggested that the combination of four dermoscopic features, whitish-pink areas, yellowish structures, polymorphous vessels and ulceration might be distinctive in extraocular sebaceous carcinoma.

Imiquimod 5% cream as a therapeutic option for extramammary Paget's disease.

A wide local excision is the standard treatment for extramammary Paget's disease (EMPD), though this treatment often leads to permanent anogenital mutilation and functional impairment. The purpose of our study is to evaluate the efficacy and safety of the topical application of imiquimod 5% cream for non-invasive EMPD. We examined nine patients with EMPD. Eight of the nine patients were treated with imiquimod 5% cream three times per week for 16 weeks; one case was treated for 6 weeks. The response rate was 100% including five complete remissions. Local irritation was observed in three patients, which was controlled by a provisional withdrawal of the treatment. These results suggest that imiquimod 5% cream may be considered an alternative therapeutic option for the treatment of non-invasive EMPD.

Serum cytokeratin 19 fragment 21-1 is a useful tumor marker for the assessment of extramammary Paget's disease.

Cytokeratin 19 fragment 21-1 (CYFRA 21-1) has been used as a tumor marker for several malignancies. However, to date, no studies have assessed whether CYFRA 21-1 could be a useful marker for extramammary Paget's disease (EMPD). The present study aimed to evaluate the significance of CYFRA 21-1 as a serum tumor marker for EMPD progression. Concentrations of serum CYFRA 21-1 and carcinoembryonic antigen (CEA) in 13 cases of EMPD were measured prior to undergoing treatment at Sapporo Medical University Hospital from January 2014 to May 2016. Four of the 13 patients had lymph node metastases at diagnosis, but none had distant metastases. Immunohistochemistry indicated that all 13 primary tumors and four metastatic tumors in lymph nodes were positive for cytokeratin 19. Although none of the 13 patients showed high serum CEA levels, six patients (46.2%) had elevated serum CYFRA 21-1. Furthermore, CYFRA 21-1 was reduced in association with post-treatment tumor reduction in all six patients. Among these six patients, four developed recurrence and metastasis during the follow-up period. CYFRA 21-1 was re-elevated in all four of these patients; however, serum CEA was elevated only in the patient with distant metastasis. These results suggest that CYFRA 21-1 is more sensitive compared with CEA, and can be useful as a tumor marker for evaluating tumor progression and treatment efficacy in patients with EMPD.