T-Cell Repertoire in Combination with T-Cell Density Predicts Clinical Outcomes in Patients with Merkel Cell Carcinoma

The integrity of the immune system represents a pivotal risk factor and prognostic biomarker for Merkel cell carcinoma. A higher density of tumor-associated T cells correlates with improved Merkel cell carcinoma-specific survival, but the prognostic importance of the T-cell infiltrate reactivity is unknown. We evaluated the T-cell receptor repertoire associated with 72 primary Merkel cell carcinomas and correlated metrics of the T-cell receptor repertoire with clinicopathologic characteristics and patient outcomes. We showed that a high Simpson's Dominance index (SDom) was significantly associated with fewer metastases (P = 0.01), lower stage at presentation (P = 0.02), lower final stage at last follow-up (P = 0.05), and longer time to first lymph node metastasis (P = 0.04). These correlations were mostly preserved in the Merkel cell polyomavirus-negative subgroup. Combining SDom with CD3⁺ or CD8⁺ T-cell density revealed three distinct prognostic groups with respect to disease-specific survival. Patients with both high SDom and high CD3⁺ or CD8⁺ T-cell density had markedly improved disease-specific survival compared with patients with low SDom and low CD3⁺ or CD8⁺ T-cell density (P = 0.002 and P = 0.03, respectively). Patients with either high SDom or high CD3⁺ or CD8⁺ had intermediate disease-specific survival. Our findings demonstrate that the quality of the tumor-associated T-cell infiltrate informs patient prognosis in primary Merkel cell carcinoma beyond the T-cell density.

Abstract A11: Prognostic model for disease-specific survival in anorectal melanoma

Background: Anorectal melanoma (AM) is generally staged using criteria developed and validated for cutaneous melanoma (CM), primarily due to its rarity and the lack of a specific staging system, despite limited evidence to support this. In an attempt to risk-stratify AM patients (pts), we analyzed the performance of the AJCC 8th edition CM staging system and a system recently developed for vulvar melanoma (VM) in a retrospective cohort.

Methods: Demographics, clinicopathologic factors, and follow-up information were collected for 160 AM pts treated at our institution. The pts were grouped based on their clinical stage at presentation (localized to anorectum [L], regional metastases [R], distant metastases [D]). For further risk stratification, L pts were grouped according to the following systems: (i) AJCC 8th edition CM T-categories (T1a to T4b, 8 tiers); (ii) AJCC 8th edition CM stage (I vs. II, 2 tiers); (iii) the tumor thickness (TT) system (thin [T1], intermediate [T2-T3], thick [T4], 3 tiers); and TM system previously derived for VM (T1: TT≤ 2.0mm and mitotic rate (MR) <2/mm2 and T2: TT >2.0mm and MR <2/mm2). Univariate (UV) and multivariable (MV) Cox proportional hazards regression modeling determined associations with disease specific survival (DSS). The Kaplan-Meier method estimated overall survival (OS) and DSS.

Results: The cohort (n=160) included 67 L, 55 R and 38 D pts. With median follow-up of 1.63 years (y), the median DSS was 1.75y for all pts. DSS progressively decreased according to stage at presentation (L: 2.39y; R: 1.81y and D: 1.25y). By UV analysis, clinical stage at presentation correlated with DSS (R: p=0.05, HR=1.52; D: p<0.001, HR=3.24, compared to L). By MV analysis (including clinical stage, tumor thickness, regression [REG], lymphovascular invasion [LVI], perineural invasion and resection margin status), the presence of distant metastasis correlated with DSS (p<0.001, HR=2.71), in addition to tumor thickness, REG, and LVI. To further optimize risk modeling and clinical management, we analyzed L pts using 4 distinct T-categorization systems. The 3-tier TT system robustly stratified DSS (p=0.03; HR- intermediate=2.36, thick=4.98, compared to thin). AJCC stage also classified 2 groups of pts according to DSS, with a trend towards significance (p=0.1; HR=3.37). In contrast, only OS models could be derived for the AJCC 8th edition T-categories (p=0.14) and TM system (p=0.1), with the latter yielding clear differences in outcomes, compared to the former. Analysis was also performed on a combined cohort of L pts with VM and AM, to determine if there are unifying themes among anogenital mucosal melanomas, and all the 4 systems stratified the pts (p<0.001), with stage, TT, and TM systems yielding clear differences in outcomes, compared to the 8 AJCC T-categories.

Conclusion: Clinical stage at presentation and T-categorization of L pts based on modifications of the 8th edition AJCC CM staging criteria (stage and TT system) appear to be potentially informative tools to stratify risk in AM pts.

Citation Format: Priyadharsini Nagarajan, JIn Piao, Jing Ning, Laura E. Noordenbos, Jonathan L. Curry, Carlos A. Torres-Cabala, A. Hafeez Diwan, Phyu P. Aung, Doina Ivan, Merrick I. Ross, Richard E. Royal, Jennifer A. Wargo, Wei-Lien Wang, Rashmi Samdani, Alexander J. Lazar, Asif Rashid, Michael A. Davies, Victor G. Prieto, Jeffrey E. Gershenwald, Michael T. Tetzlaff. Prognostic model for disease-specific survival in anorectal melanoma [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr A11.

Hypertrophic lichenoid dermatitis immune-related adverse event during combined immune checkpoint and exportin inhibitor therapy: A diagnostic pitfall for superficially invasive squamous cell carcinoma

Immune checkpoint inhibitors (ICIs) for cancer treatment have revolutionized the field of medicine. However, an unintended but frequent consequence of ICI therapy is the development of cutaneous immune-related adverse events (irAEs), such as lichenoid dermatitis irAEs (LD-irAEs). The hypertrophic variant of LD-irAE may be a diagnostic challenge since it can mimic superficially invasive squamous cell carcinoma (SCC). A 79-year-old woman with metastatic melanoma who began treatment with an ICI-pembrolizumab-plus exportin-1 (XPO1) inhibitor presented after 1 month of therapy with symmetrical violaceous papules coalescing into plaques and with two nodules of the bilateral dorsal hands. Biopsy of the nodules revealed an actinic keratosis and atypical epidermal proliferation concerning for SCC. However, in the ensuing 3 weeks, the patient developed multiple new erythematous, violaceous, and scaly macules and papules, some coalescing into plaques on the extremities. Biopsies of these lesions revealed exuberant irregular epidermal hyperplasia with hypermaturation and lichenoid infiltrate concentrated at the base of the elongated, broadened rete ridges, consistent with hypertrophic LD-irAE. Treatment included topical fluocinonide ointment, intralesional triamcinolone injections and oral acitretin. Distinguishing hypertrophic LD-irAE and SCC can be challenging since both entities share histopathologic features; thus, correlation with clinical presentation is essential for diagnosis and optimal patient management.

TERT amplification but not activation of canonical Wnt/β-catenin pathway is involved in acral lentiginous melanoma progression to metastasis

Acral lentiginous melanoma (ALM) is a rare tumor that occurs on non-sun exposed skin areas of the hands and feet. Reports suggest that ALM exhibits poor prognosis, although mechanisms driving this remain poorly understood. Alterations in TERT and the Wnt/β-catenin (Wnt) pathway have been suggested to correlate with prognosis of ALM. Thus, immunohistochemical expression of β-catenin and LEF1 along with TERT amplification by FISH was investigated in 34 primary ALMs, 20 metastatic ALMs, 10 primary non-ALMs, and 15 acral nevi. Foot/toe was the most common primary tumor location (85%) for ALM. TERT amplification was detected in 6 of 28 (21.4%) primary ALM, 2 of 8 (25%) primary non-ALM, and 8 of 18 (44.4%) metastatic ALM, the latter showing significantly higher frequency compared with primary melanomas (P = 0.043). Most metastatic ALMs positive for TERT amplification lacked BRAF V600E (87.5%). Cytoplasmic and nonnuclear expression of β-catenin was variably detected in all cases. Metastatic ALM revealed lower expression of β-catenin compared with primary ALM (P = 0.017). No differences in LEF1 expression were detected among the groups; however, acral nevi showed decreased labeling with dermal descent, in contrast to melanoma. No molecular-genetic alteration correlated with prognosis. TERT amplification by FISH is a frequent finding in primary ALM and appears to increase in metastatic tumors, suggesting a role in tumor progression to metastasis. Although TERT amplification has been reported to be infrequent in primary non-ALM, it showed comparable frequency with ALM in our series. Our immunohistochemical findings are not fully supportive of activation of either canonical or noncanonical Wnt cascades in ALM. TERT amplification by FISH and LEF1 immunohistochemistry may help in the differential diagnosis between primary ALM and acral nevus. TERT amplification appears to be a promising target for therapy in patients with metastatic ALM.

Cutaneous adnexal carcinosarcoma: Immunohistochemical and molecular evidence of epithelial mesenchymal transition

Cutaneous carcinosarcomas are rare biphenotypic tumors that simultaneously show epithelial and mesenchymal differentiation. The most common carcinomatous components in skin carcinosarcomas are basal cell carcinoma and squamous cell carcinoma; adnexal carcinomas are rarely encountered. We report a case of an adnexal carcinoma with ductal and squamous differentiation and spindle cell component, which is interpreted as carcinosarcoma. Loss of immunohistochemical expression of E-cadherin and β-catenin detected in the sarcomatous component suggested epithelial mesenchymal transition (EMT). RNA sequencing analysis identified several gene mutations and alterations such as translocations and upregulations/downregulations, either shared by the two components of the tumor or differentially present in the carcinoma or the sarcoma parts. Thus, mutations in genes, such as TP53, were found in both components of the tumor while mutations in PDGFRA and RB1 (a pathogenic missense mutation) were exclusively present in the sarcomatous areas, further supporting EMT. EMT is a dynamic process by which tumors acquire mesenchymal phenotype while simultaneously losing epithelial properties. Although the pathways involved in EMT have been extensively studied, this phenomenon still needs to be investigated in cutaneous tumors of adnexal origin for a better understanding of their pathogenesis. These molecular changes may represent promising targets for personalized therapies.

Langerhans cell sarcoma involving skin and showing epidermotropism: A comprehensive review

Langerhans cell sarcoma (LCS) is rare and aggressive; patients have an overall survival rate of less than 50%. We present a 62-year-old man with a history of superficial spreading melanoma of the upper back with sentinel lymph node metastasis, Langerhans cell histiocytosis, and LCS. The patient presented with erythematous papules and scaly areas on his face, neck, arms, chest, abdomen, and legs. A skin biopsy revealed a proliferation of large neoplastic cells involving the dermis and with epidermotropism. These cells had atypical bean-shaped nuclei, with ample cytoplasm and abundant mitotic figures including atypical forms. Immunohistochemical studies showed the tumor to be diffusely positive for CD1a, S100 protein, and langerin (CD207) and negative for melanocytic markers. Some tumor cells were positive for cyclin D1. A diagnosis of LCS involving the skin was established. The present study is a very unusual case of LCS showing epidermotropism. The patient's history of metastatic melanoma posed additional challenges for diagnosis, underlying the need of immunophenotyping in these cases. Consensus for optimal standard therapy has not been established in LCS, and thus, early recognition is important since these neoplasms tend to recur and metastasize. LCS in skin is discussed and published cases are comprehensively reviewed.

Epithelioid angiomyolipoma mimicking metastatic melanoma in a liver tumor

It is well known to pathologists that melanoma is "the great mimicker," looking like almost any other tumor, and able to metastasize anywhere in the body. We report a case of a 48-year-old female with a history of metastatic melanoma 4 years before, who presented with a hepatic mass. Microscopic examination of the liver mass revealed sheets of pleomorphic, epithelioid cells, which expressed a pan-melanocytic cocktail (MART1, HMB45, and tyrosinase). These findings were initially interpreted as metastatic melanoma and the case was transferred for dermatopathology consultation. We compared the morphology of this tumor to the primary melanoma and noticed that the primary melanoma showed nevoid cytology, morphologically distinct from the liver lesion. Consequently, we performed additional immunohistochemical studies, which determined that the liver mass was negative for S100 and SOX10, and established a final diagnosis of epithelioid angiomyolipoma. The key for reaching the correct diagnosis was the morphologic comparison with the original lesion and the evaluation of a wider immunohistochemical profile. For appropriate management in patients with new lesions, even in the context of a patient with known metastatic disease, it is essential to consider other neoplasms in the differential diagnosis.

Abstract P3-08-38: Primary cutaneous melanoma of the breast in women. A retrospective study of 82 patients

Background: Primary cutaneous melanoma of the breast (PCMB) is a relatively uncommon type of melanoma staged according to the AJCC system for other cutaneous melanomas. However, whether their outcome is different from primary cutaneous melanomas of other sun-exposed sites and the features that predict outcome specifically in PCMB are currently unclear. Moreover, histologically, the breast skin is considered to be a special site for melanocytic lesions. Therefore, we analyzed a retrospective cohort of female PCMB patients to determine the clinical and primary tumor features that correlate with time-to-event outcomes of overall survival (OS) and disease specific survival (DSS).

Design: We identified women with PCMB diagnosed and/or treated at our institution between 2002 and 2015. The following data were collected: clinical/ demographic features (age at diagnosis, ethnicity, anatomic site [nipple-areolar complex, upper, lower, medial, lateral]); primary tumor pathologic features (Breslow thickness, Clark level, ulceration, mitotic rate, vertical growth phase (VGP), regression, lymphovascular invasion (LVI), perineural invasion (PNI), tumor infiltrating lymphocytes (TIL) and cytology); and metastatic disease features (satellitosis, date and metastasis to sentinel and/or regional lymph nodes, clinical detectability of nodal metastasis, and date and site of distant metastases). Kaplan Meier methods, univariate and multivariate Cox proportional hazards regression models determined associations with OS and DSS.

Results: 82 cases, including 16 in-situ and 66 invasive PCMBs were identified. Most patients were white (98%), with a median age at diagnosis of 40.5 years (range: 15-77). With a median follow up of 7.6 years, the 1, 3, 5, 10-year OS rates were 97.4%, 94.7%, 91.9% and 81.3%, respectively; the 1, 3, 5, 10-year DSS rates were 98.7%, 95.9%, 93.1% and 86.9%, respectively; the median OS and DSS were not reached. Thirteen patients developed metastasis: 5 regional only, 1 distant only and 7 both; of which 6 had metastatic disease at presentation. Eleven patients died, and 8 was due to progression of PCMB. Most of the invasive PCMB were of superficial spreading type (84.8%), with median tumor thickness of 0.47 mm. Univariate analysis of patients with invasive melanoma revealed the following features to be associated with shorter survival (Table 1): age at presentation, Breslow thickness, Clark level, ulceration, mitotic rate and VGP; while histologic type, anatomic site, LVI, PNI, regression, associated nevus, cytology, and TIL were not significant. Adjusting covariate of features significant in univariate analysis, the multivariate analysis demonstrated only Breslow thickness and ulceration to be independently associated with OS and DSS.

Conclusion: Primary cutaneous melanomas of the breast often affects white adult women and increasing tumor thickness and ulceration are associated with shorter survival, similar to primary melanomas of other cutaneous sites.

Table 1: Clinical and Primary Tumor Features Associated with Overall (OS) and Disease Specific Survival (DSS) in Primary Cutaneous Melanomas of the BreastUnivariate Analysis (p-value)Clinical/ primary tumor featureOSDSSAge at presentation ≥ 41.5 years0.0020.018Breslow Thickness0.0020.001Clark Level0.0040.003Vertical Growth Phase0.0430.038Mitotic Rate0.001<0.001Ulceration<0.001<0.001Regression0.2870.195Tumor Infiltrating Lymphocytes0.1370.278Lymphovascular Invasion0.1980.147Associated Nevus0.830.41Predominant Cytology0.7280.874Multivariate Analysis (p-value)Breslow Thickness0.0140.006Ulceration0.0060.017

Citation Format: Madhuchhanda Roy, Junsheng Ma, Aysegul A Sahin, Senthilkumar Damodaran, Michael T Tetzlaff, Jonathan L Curry, Ana M Ciurea, Jing Ning, Carlos A Torres-Cabala, Doina Ivan, Phyu P Aung, Merrick I Ross, Jeffrey E Gershenwald, Michael A Davies, Victor G Prieto and Priyadharsini Nagarajan. Primary cutaneous melanoma of the breast in women. A retrospective study of 82 patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-38.

Lichen planus related to transforming growth factor beta inhibitor in a patient with metastatic chondrosarcoma: a case report

Transforming growth factor-beta1 (TGF-β1) is expressed in normal epidermis. TGF-β1 potently inhibits keratinocyte proliferation and immunomodulatory properties, mainly by suppressing immune responses to self-antigens. Lichen planus (LP) is a form of dermatitis caused by cell-mediated immune dysfunction, but the exact pathogenic pathways are unknown, which poses therapeutic challenges. We report on a 68-year-old man who developed multiple pruritic, discrete, and well-demarcated, flat-topped red-purple papules and macules on the back and upper arms following 4 cycles of treatment with TGF-β receptor I (TGFBR-I) inhibitor, ly3200882, for metastatic chondrosarcoma. The biopsy showed hyperkeratosis, wedge-shaped hypergranulosis, elongation of the rete ridges, and a dense band-like lymphohistiocytic infiltrate admixed with colloid bodies and pigment incontinence, consistent with LP. Temporal correlation suggested that the TGFBR-I inhibitor might be a trigger. Treatment with topical clobetasol and oral metronidazole led to partial resolution of the lesions with postinflammatory hyperpigmentation. We believe this is the first reported case of LP related to TGFBR-I inhibitor therapy. This report expands the list of cutaneous adverse events associated with this novel class of targeted therapy. More importantly, this report supports emerging evidence that failure of TGF-β1 activation/signal transduction is an important mechanism in the pathogenesis of LP and suggests the TGF-β1 pathway as a potential therapeutic target in this disease.

Cutaneous neoplasms composed of melanoma and carcinoma: A rare but important diagnostic pitfall and review of the literature

We report two cases of combined cutaneous tumors composed of melanoma and carcinoma. The first tumor presented as a 5-mm pink-blue macule over the right zygomatic arch in an 85-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of melanoma (highlighted by SOX10 and MART-1, with high Ki-67 proliferative index) intermixed with nodular basal cell carcinoma (highlighted by pan-cytokeratin and Ber-EP4). The neoplastic melanocytes were confined to the basal cell carcinoma nodules, and a diagnosis of combined melanoma in situ and basal cell carcinoma was rendered. After therapeutic excision, the patient was disease-free at 9 months after the initial diagnosis. The second tumor presented as a 6-mm pink-brown crusted papule on the right forehead in an 89-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of malignant melanoma (MM) (highlighted by S100 and MART-1) intermixed with squamous cell carcinoma (SCC) (highlighted by cytokeratin and p63), and a diagnosis of combined MM-SCC was rendered. These two cases highlight the importance of recognizing these rare types of melanocytic-epithelial cutaneous neoplasms to arrive at an accurate diagnosis that may inform appropriate disease stage and therapy.

Aberrant DNA Methylation Predicts Melanoma-Specific Survival in Patients with Acral Melanoma

Acral melanoma (AM) is a rare, aggressive type of cutaneous melanoma (CM) with a distinct genetic profile. We aimed to identify a methylome signature distinguishing primary acral lentiginous melanoma (PALM) from primary non-lentiginous AM (NALM), metastatic ALM (MALM), primary non-acral CM (PCM), and acral nevus (AN). A total of 22 PALM, nine NALM, 10 MALM, nine PCM, and three AN were subjected to genome-wide methylation analysis using the Illumina Infinium Methylation EPIC array interrogating 866,562 CpG sites. A prominent finding was that the methylation profiles of PALM and NALM were distinct. Four of the genes most differentially methylated between PALM and NALM or MALM were HHEX, DIPK2A, NELFB, and TEF. However, when primary AMs (PALM + NALM) were compared with MALM, IFITM1 and SIK3 were the most differentially methylated, highlighting their pivotal role in the metastatic potential of AMs. Patients with NALM had significantly worse disease-specific survival (DSS) than patients with PALM. Aberrant methylation was significantly associated with aggressive clinicopathologic parameters and worse DSS. Our study emphasizes the importance of distinguishing the two epigenetically distinct subtypes of AM. We also identified novel epigenetic prognostic biomarkers that may serve to risk-stratify patients with AM and may be leveraged for the development of targeted therapies.

Correlation of Tumor Burden in Sentinel Lymph Nodes with Tumor Burden in Nonsentinel Lymph Nodes and Survival in Cutaneous Melanoma

PURPOSE

In patients with cutaneous melanoma, metastasis in a nonsentinel lymph node (non-SLN) is a strong independent adverse prognostic factor. However, patients with a tumor-involved SLN no longer routinely undergo completion lymph node dissection (CLND). We hypothesized that SLN tumor burden may predict non-SLN tumor burden.

EXPERIMENTAL DESIGN

We compared tumor burden parameters between SLN and non-SLN in patients with cutaneous melanoma who underwent SLN biopsy with a positive SLN during 2003 to 2008 at The University of Texas MD Anderson Cancer Center.

RESULTS

We identified 336 eligible patients with a positive SLN. Of these, 308 (92%) underwent CLND, and 35 (10%) had non-SLN metastasis. The median follow-up time was 6.0 years. For patients with maximum diameter of tumor in the SLN ≤2.0 mm, >2.0-5.0 mm, and >5.0 mm, non-SLN metastasis was detected in 5 of 200 patients (3%), 10 of 63 patients (16%), and 20 of 57 patients (35%), and the mean maximum diameters of the non-SLN tumor deposits were 0.09, 1.56, and 2.71 mm, respectively (P < 0.0001). The percentage of patients with both subcapsular and intraparenchymal non-SLN tumor was higher for patients with SLN tumor in both locations than for patients with SLN tumor in only one location (P < 0.0001). Extranodal extension in a non-SLN was more common in patients with extranodal extension in an SLN (P = 0.003).

CONCLUSIONS

In patients with cutaneous melanoma who undergo CLND, SLN tumor burden predicts non-SLN tumor burden. SLN tumor burden parameters provide accurate prognostic stratification independent of non-SLN status and should be considered for incorporation into future staging systems and integrated risk models.

Role of angiogenesis in melanoma progression: Update on key angiogenic mechanisms and other associated components

Angiogenesis, the formation of new blood vessels from existing blood vessels, is a complex and highly regulated process that plays a role in a wide variety of physiological and pathological processes. In malignancy, angiogenesis is essential for neoplastic cells to acquire the nutrients and oxygen critical for their continued proliferation. Angiogenesis requires a sequence of well-coordinated events mediated by a number of tightly regulated interactions between pro-angiogenic factors and their corresponding receptors expressed on various vascular components (e.g., endothelial cells and pericytes) and stromal components forming the extracellular matrix. In this review, we discuss the functional roles of key growth factors and cytokines known to promote angiogenesis in cutaneous melanoma and key factors implicated in the extracellular matrix remodeling that acts synergistically with angiogenesis to promote tumor progression in melanoma, incorporating some of the most up-to-date basic science knowledge from recently published in vivo and in vitro experimental studies.

Unusual cutaneous metastatic carcinoma

Most of metastatic tumors to the skin are from primary tumors of the breast, lung, or from melanoma; metastases to the skin from primary carcinomas at other sites are rare. Cutaneous metastases of visceral carcinomas most often occur in patients with advanced disease, and are associated with a poor prognosis. We report 6 cases of nonmammary, nonpulmonary carcinoma metastatic to the skin. Most patients were elderly with advanced disease at the time of diagnosis of skin metastasis. The primary tumor sites included the thyroid, esophagus, biliary tract, ovary, and prostate. Awareness of these rare cases of metastasis to the skin will help pathologists and clinicians make the correct diagnosis.

Immunohistochemical and Molecular Features of Melanomas Exhibiting Intratumor and Intertumor Histomorphologic Heterogeneity

Melanoma is a heterogeneous neoplasm at the histomorphologic, immunophenotypic, and molecular levels. Melanoma with extreme histomorphologic heterogeneity can pose a diagnostic challenge in which the diagnosis may predominantly rely on its immunophenotypic profile. However, tumor survival and response to therapy are linked to tumor genetic heterogeneity rather than tumor morphology. Therefore, understating the molecular characteristics of such melanomas become indispensable. In this study, DNA was extracted from 11 morphologically distinct regions in eight formalin-fixed, paraffin-embedded melanomas. In each region, mutations in 50 cancer-related genes were tested using next-generation sequencing (NGS). A tumor was considered genetically heterogeneous if at least one non-overlapping mutation was identified either between the histologically distinct regions of the same tumor (intratumor heterogeneity) or among the histologically distinct regions of the paired primary and metastatic tumors within the same patient (intertumor heterogeneity). Our results revealed that genetic heterogeneity existed in all tumors as non-overlapping mutations were detected in every tested tumor (n = 5, 100%; intratumor: n = 2, 40%; intertumor: n = 3, 60%). Conversely, overlapping mutations were also detected in all the tested regions (n = 11, 100%). Melanomas exhibiting histomorphologic heterogeneity are often associated with genetic heterogeneity, which might contribute to tumor survival and poor response to therapy.

The "-OMICS" facet of melanoma: Heterogeneity of genomic, proteomic and metabolomic biomarkers

In the recent decade, cutting edge molecular and proteomic analysis platforms revolutionized biomarkers discovery in cancers. Melanoma is the prototype with over 51,100 biomarkers discovered and investigated thus far. These biomarkers include tissue based tumor cell and tumor microenvironment biomarkers and circulating biomarkers including tumor DNA (cf-DNA), mir-RNA, proteins and metabolites. These biomarkers provide invaluable information for diagnosis, prognosis and play an important role in prediction of treatment response. In this review, we summarize the most recent discoveries in each of these biomarker categories. We will discuss the challenges in their implementation and standardization and conclude with some perspectives in melanoma biomarker research.

PD1/PD-L1 Expression in Blastic Plasmacytoid Dendritic Cell Neoplasm

Patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN) have poor outcomes despite intensive chemotherapy, underscoring the need for novel therapeutic approaches. The expression status of PD1/PD-L1 in BPDCN remains unknown. We evaluated PD1/PD-L1 by immunohistochemistry and RNAseq expression profiling in a cohort of BPDCN patients. The study group included 28 patients with a median age of 66.8 years (range, 22.8–86.7), 22 men and 6 women. PD-L1 expression was detected by immunohistochemistry in 10/21 (47.6%) cases. PD-L1 expression had a median H-score of 157. The H-score was ≥60 in 7 patients. PD-L1 protein levels (H-score) were proportional to normalized PD-L1 mRNA transcript levels (CD274 mRNA). In addition, high-level PD-L1 expression correlated with higher numbers of PD1-positive cells within BPDCN tumors. There was no correlation between clinicopathologic characteristics and PD-L1 expression status. Similarly, there was no significant difference in overall survival between patients with PD-L1-positive and PD-L1-negative BPDCN (median 12 vs. 23 month, respectively; p = 0.743). In conclusion, PD-L1 expression by tumor cells is detectable in a sizeable subset of patients with BPDCN, suggesting that exploration of the effectiveness of therapeutic inhibition of the PD1/PD-L1 axis in patients with refractory or progressive BPDCN is warranted.

Complete Resolution of Primary Cutaneous Anaplastic Large Cell Lymphoma With Topical Imiquimod

Primary cutaneous anaplastic large cell lymphoma (pc-ALCL) is a CD30+ subtype of cutaneous T-cell lymphoma. It typically has a very favorable prognosis; however, traditional treatment can be expensive, invasive, and associated with significant adverse events. Imiquimod is a topical toll-like receptor approved by the Food and Drug Administration (FDA) for genital warts, actinic keratosis, and primary superficial basal cell carcinoma. In previous case reports, imiquimod has been shown to be effective against pc-ALCL. We present a case of complete resolution of pc-ALCL within 8 weeks with topical imiquimod and review the current literature. J Drugs Dermatol. 2019;18(5):460-462.