Early switch from run-in treatment with vemurafenib plus cobimetinib to atezolizumab after 3 months leads to rapid loss of tumour control in patients with advanced BRAFV600-positive melanoma: The ImmunoCobiVem phase 2 randomised trial.

AIM: ImmunoCobiVem investigated whether a planned switch to atezolizumab after achieving tumour control during run-in with vemurafenib + cobimetinib improves progression-free survival (PFS) and overall survival (OS) compared to continuous targeted therapy (TT) in patients with previously untreated advanced BRAFV600-mutated melanoma. METHODS: In this multicenter phase 2 study, patients received vemurafenib plus cobimetinib. After 3months, patients without progressive disease (PD) were randomly assigned (1:1) to continue vemurafenib + cobimetinib (Arm A) or switch to atezolizumab (Arm B) until first documented PD (PD1). Primary outcome was PFS1 (time from start of run-in until PD1 or death). OS and safety were also assessed. RESULTS: Of 185 patients enroled between November 2016 and December 2019, 135 were randomly assigned after the run-in period (Arm A, n = 69; Arm B, n = 66). Median PFS1 was significantly longer in Arm A versus Arm B (13.9 versus 5.9months; hazard ratio [HR] 0.55; 95% confidence interval [CI], 0.37-0.84; PStratified=0.001). Median OS was not reached in either arm (HR 1.22; 95%CI, 0.69-2.16; PStratified=0.389); 2-year OS was higher in Arm B versus Arm A (67%; 95%CI, 53-78 versus 58%; 95%CI, 45-70). Grade 3/4 AEs occurred in 55% of patients in Arm A and 64% in Arm B; treatment-related AEs led to discontinuation of any drug in 7% and 9% of patients, respectively. CONCLUSION: In patients with BRAFV600-mutated advanced melanoma who achieve tumour control with TT, early switch at 3months to atezolizumab led to rapid loss of tumour control but provided a numerical OS benefit at 2years compared with continued TT.

GNAQ and GNA11 mutant nonuveal melanoma: a subtype distinct from both cutaneous and uveal melanoma.

BACKGROUND: GNAQ and GNA11 mutant nonuveal melanoma represent a poorly characterized rare subgroup of melanoma with a gene mutation profile similar to uveal melanoma. OBJECTIVES: To characterize these tumours in terms of clinical behaviour and genetic characteristics. METHODS: Patients with nonuveal GNAQ/11 mutated melanoma were identified from the prospective multicentre tumour tissue registry ADOREG, Tissue Registry in Melanoma (TRIM) and additional cooperating skin cancer centres. Extensive data on patient, tumour and treatment characteristics were collected retrospectively. Targeted sequencing was used to determine tumour mutational burden. Immunohistochemistry staining was performed for programmed death-ligand 1 and BRCA1-associated protein (BAP)1. Existing whole-exome cutaneous and uveal melanoma data were analysed for mutation type and burden. RESULTS: We identified 18 patients with metastatic GNAQ/11 mutant nonuveal melanoma. Tumours had a lower tumour mutational burden and fewer ultraviolet signature mutations than cutaneous melanomas. In addition to GNAQ and GNA11 mutations (nine each), six splicing factor 3b subunit 1 (SF3B1), three eukaryotic translation initiation factor 1A X-linked (EIF1AX) and four BAP1 mutations were detected. In contrast to uveal melanoma, GNAQ/11 mutant nonuveal melanomas frequently metastasized lymphatically and concurrent EIF1AX, SF3B1 and BAP1 mutations showed no apparent association with patient prognosis. Objective response to immunotherapy was poor with only one partial response observed in 10 treated patients (10%). CONCLUSIONS: Our findings suggest that GNAQ/11 mutant nonuveal melanomas are a subtype of melanoma that is both clinically and genetically distinct from cutaneous and uveal melanoma. As they respond poorly to available treatment regimens, novel effective therapeutic approaches for affected patients are urgently needed. What is already known about this topic? The rare occurrence of GNAQ/11 mutations in nonuveal melanoma has been documented. GNAQ/11 mutant nonuveal melanomas also harbour genetic alterations in EIF1AX, SF3B1 and BAP1 that are of prognostic relevance in uveal melanoma. What does this study add? GNAQ/11 mutant nonuveal melanomas show metastatic spread reminiscent of cutaneous melanoma, but not uveal melanoma. GNAQ/11 mutant nonuveal melanomas have a low tumour mutational burden that is higher than uveal melanoma, but lower than cutaneous melanoma. What is the translational message? Primary GNAQ/11 mutant nonuveal melanomas are a subtype of melanoma that is clinically and genetically distinct from both cutaneous and uveal melanoma. As metastatic GNAQ/11 mutant nonuveal melanomas respond poorly to available systemic therapies, including immune checkpoint inhibition, novel therapeutic approaches for these tumours are urgently needed. Linked Comment: Rafei-Shamsabadi. Br J Dermatol 2020; 183:806-807.

Elevated baseline serum PD-1 or PD-L1 predicts poor outcome of PD-1 inhibition therapy in metastatic melanoma.

BACKGROUND: Programmed cell death protein 1 (PD-1) checkpoint inhibition has recently advanced to one of the most effective treatment strategies in melanoma. Nevertheless, a considerable proportion of patients show upfront therapy resistance and baseline predictive biomarkers of treatment outcome are scarce. In this study we quantified PD-1 and programmed death-ligand 1 (PD-L1) in baseline sera from melanoma patients in relation to therapy response and survival. PATIENTS AND METHODS: Sera taken at therapy baseline from a total of 222 metastatic melanoma patients (two retrospectively selected monocentric discovery cohorts, n = 130; one prospectively collected multicentric validation cohort, n = 92) and from 38 healthy controls were analyzed for PD-1 and PD-L1 concentration by sandwich enzyme-linked immunosorbent assay. RESULTS: Melanoma patients showed higher serum concentrations of PD-1 (P = 0.0054) and PD-L1 (P < 0.0001) than healthy controls. Elevated serum PD-1 and PD-L1 levels at treatment baseline were associated with an impaired best overall response (BOR) to anti-PD-1 (P = 0.014, P = 0.041), but not to BRAF inhibition therapy. Baseline PD-1 and PD-L1 serum levels correlated with progression-free (PFS; P = 0.0081, P = 0.053) and overall survival (OS; P = 0.055, P = 0.0062) in patients who received anti-PD-1 therapy, but not in patients treated with BRAF inhibitors. By combining both markers, we obtained a strong discrimination between favorable and poor outcome of anti-PD-1 therapy, with elevated baseline serum levels of PD-1 and/or PD-L1 associated with an impaired BOR (P = 0.037), PFS (P = 0.048), and OS (P = 0.0098). This PD-1/PD-L1 combination serum biomarker was confirmed in an independent multicenter validation set of serum samples prospectively collected at baseline of PD-1 inhibition (BOR, P = 0.019; PFS, P = 0.038; OS, P = 0.022). Multivariable Cox regression demonstrated serum PD-1/PD-L1 as an independent predictor of PFS (P = 0.010) and OS (P = 0.003) in patients treated with PD-1 inhibitors. CONCLUSION: Our findings indicate PD-1 and PD-L1 as useful serum biomarkers to predict the outcome of PD-1 inhibition therapy in melanoma patients and to select patients for PD-1-based versus BRAF-based therapy strategies.

Sequence-dependent cross-resistance of combined radiotherapy plus BRAFV600E inhibition in melanoma.

INTRODUCTION: Treatment of patients with metastatic melanoma is hampered by drug-resistance and often requires combination with radiotherapy as last-resort option. However, also after radiotherapy, clinical relapses are common. METHODS & RESULTS: Our preclinical models indicated a higher rate of tumour relapse when melanoma cells were first treated with BRAFV600E inhibition (BRAFi) followed by radiotherapy as compared to the reverse sequence. Accordingly, retrospective follow-up data from 65 stage-IV melanoma patients with irradiated melanoma brain metastases confirmed a shortened duration of local response of mitogen-activated protein kinase (MAPK)-inhibitor-pretreated compared with MAPK-inhibitor-naïve intracranial metastases. On the molecular level, we identified JARID1B/KDM5B as a cellular marker for cross-resistance between BRAFi and radiotherapy. JARID1Bhigh cells appeared more frequently under upfront BRAFi as compared with upfront radiation. JARID1B favours cell survival by transcriptional regulation of genes controlling cell cycle, DNA repair and cell death. CONCLUSION: The level of cross-resistance between combined MAPK inhibition and radiotherapy is dependent on the treatment sequence. JARID1B may represent a novel therapy-overarching resistance marker.

Detection of ABCB5 tumour antigen-specific CD8+ T cells in melanoma patients and implications for immunotherapy.

ATP binding cassette subfamily B member 5 (ABCB5) has been identified as a tumour-initiating cell marker and is expressed in various malignancies, including melanoma. Moreover, treatment with anti-ABCB5 monoclonal antibodies has been shown to inhibit tumour growth in xenotransplantation models. Therefore, ABCB5 represents a potential target for cancer immunotherapy. However, cellular immune responses against ABCB5 in humans have not been described so far. Here, we investigated whether ABCB5-reactive T cells are present in human melanoma patients and tested the applicability of ABCB5-derived peptides for experimental induction of human T cell responses. Peripheral blood mononuclear cells (PBMNC) isolated from blood samples of melanoma patients (n = 40) were stimulated with ABCB5 peptides, followed by intracellular cytokine staining (ICS) for interferon (IFN)-γ and tumour necrosis factor (TNF)-α. To evaluate immunogenicity of ABCB5 peptides in naive healthy donors, CD8 T cells were co-cultured with ABCB5 antigen-loaded autologous dendritic cells (DC). ABCB5 reactivity in expanded T cells was assessed similarly by ICS. ABCB5-reactive CD8+ T cells were detected ex vivo in 19 of 29 patients, melanoma antigen recognised by T cells (MART-1)-reactive CD8+ T cells in six of 21 patients. In this small, heterogeneous cohort, reactivity against ABCB5 was significantly higher than against MART-1. It occurred significantly more often and independently of clinical characteristics. Reactivity against ABCB5 could be induced in 14 of 16 healthy donors in vitro by repeated stimulation with peptide-loaded autologous DC. As ABCB5-reactive CD8 T cells can be found in the peripheral blood of melanoma patients and an ABCB5-specific response can be induced in vitro in naive donors, ABCB5 could be a new target for immunotherapies in melanoma.

Dabrafenib plus trametinib versus dabrafenib monotherapy in patients with metastatic BRAF V600E/K-mutant melanoma: long-term survival and safety analysis of a phase 3 study.

BACKGROUND: Previous analysis of COMBI-d (NCT01584648) demonstrated improved progression-free survival (PFS) and overall survival (OS) with combination dabrafenib and trametinib versus dabrafenib monotherapy in BRAF V600E/K-mutant metastatic melanoma. This study was continued to assess 3-year landmark efficacy and safety after ≥36-month follow-up for all living patients. PATIENTS AND METHODS: This double-blind, phase 3 study enrolled previously untreated patients with BRAF V600E/K-mutant unresectable stage IIIC or stage IV melanoma. Patients were randomized to receive dabrafenib (150 mg twice daily) plus trametinib (2 mg once daily) or dabrafenib plus placebo. The primary endpoint was PFS; secondary endpoints were OS, overall response, duration of response, safety, and pharmacokinetics. RESULTS: Between 4 May and 30 November 2012, a total of 423 of 947 screened patients were randomly assigned to receive dabrafenib plus trametinib (n = 211) or dabrafenib monotherapy (n = 212). At data cut-off (15 February 2016), outcomes remained superior with the combination: 3-year PFS was 22% with dabrafenib plus trametinib versus 12% with monotherapy, and 3-year OS was 44% versus 32%, respectively. Twenty-five patients receiving monotherapy crossed over to combination therapy, with continued follow-up under the monotherapy arm (per intent-to-treat principle). Of combination-arm patients alive at 3 years, 58% remained on dabrafenib plus trametinib. Three-year OS with the combination reached 62% in the most favourable subgroup (normal lactate dehydrogenase and <3 organ sites with metastasis) versus only 25% in the unfavourable subgroup (elevated lactate dehydrogenase). The dabrafenib plus trametinib safety profile was consistent with previous clinical trial observations, and no new safety signals were detected with long-term use. CONCLUSIONS: These data demonstrate that durable (≥3 years) survival is achievable with dabrafenib plus trametinib in patients with BRAF V600-mutant metastatic melanoma and support long-term first-line use of the combination in this setting.

[Single center analysis of the dermatosurgical patient cohort of a tumor center in Germany]. / Betrachtung des dermatochirurgischen Patientenkollektivs an einem Hauttumorzentrum in Deutschland.

BACKGROUND: The incidence of skin cancer continues to increase. However, little is known about the dermatosurgical characteristics of the patients. PATIENTS AND METHODS: In this single center, retrospective study, dermatosurgical reports of all patients treated because of basal cell carcinomas (BCC), squamous cell carcinomas (SCC), and malignant melanoma (MM) between 2004 and 2013 were analyzed. RESULTS: During the observed period, the number of operated BCC rose by a factor of 1.86 and the number of MM by a factor of 2.3. In comparison to BCC/MM, there was a disproportionately high increase of SCC by a factor of 4.02. The average age was 71.5 ± 13.4 years (minimum: 14 years; maximum: 104 years), whereupon a significant increase of male age and a significant decrease of female age occurred. Almost 70% of all tumors were located in the head and neck area. The nose was most commonly treated. CONCLUSIONS: During the last 10 years, the cohort of dermatosurgical patients changed in the tumor center. This should be verified in multicenter studies.

Safety and immunogenicity of the PRAME cancer immunotherapeutic in metastatic melanoma: results of a phase I dose escalation study.

PURPOSE: The PRAME tumour antigen is expressed in several tumour types but in few normal adult tissues. A dose-escalation phase I/II study (NCT01149343) assessed the safety, immunogenicity and clinical activity of the PRAME immunotherapeutic (recombinant PRAME protein (recPRAME) with the AS15 immunostimulant) in patients with advanced melanoma. Here, we report the phase I dose-escalation study segment. PATIENTS AND METHODS: Patients with stage IV PRAME-positive melanoma were enrolled to 3 consecutive cohorts to receive up to 24 intramuscular injections of the PRAME immunotherapeutic. The RecPRAME dose was 20, 100 or 500 µg in cohorts 1, 2 and 3, respectively, with a fixed dose of AS15. Adverse events (AEs), including predefined dose-limiting toxicity (DLT) and the anti-PRAME humoral response (ELISA), were coprimary end points. Cellular immune responses were evaluated using in vitro assays. RESULTS: 66 patients were treated (20, 24 and 22 in the respective cohorts). AEs considered by the investigator to be causally related were mostly grade 1 or 2 injection site symptoms, fatigue, chills, fever and headache. Two DLTs (grade 3 brain oedema and proteinuria) were recorded in two patients in two cohorts (cohorts 2 and 3). All patients had detectable anti-PRAME antibodies after four immunisations. Percentages of patients with predefined PRAME-specific-CD4+T-cell responses after four immunisations were similar in each cohort. No CD8+ T-cell responses were detected. CONCLUSIONS: The PRAME immunotherapeutic had an acceptable safety profile and induced similar anti-PRAME-specific humoral and cellular immune responses in all cohorts. As per protocol, the phase II study segment was initiated to further evaluate the 500 µg PRAME immunotherapeutic dose. TRIAL REGISTRATION NUMBER: NCT01149343, Results.

Serum inflammatory factors and circulating immunosuppressive cells are predictive markers for efficacy of radiofrequency ablation in non-small-cell lung cancer.

In recent years, percutaneous radiofrequency ablation (RFA) has been developed as a new tool in the treatment of non-small-cell lung cancer (NSCLC) in non-surgical patients. There is growing evidence that RFA-mediated necrosis can modulate host immune responses. Here we analysed serum inflammatory factors as well as immunosuppressive cells in the peripheral blood to discover possible prognostic indicators. Peripheral blood and serum samples were collected before RFA and within 3 months after the treatment in a total of 12 patients. Inflammatory cytokines and growth factors were measured in serum by the Bio-Plex assay. Myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs ) were evaluated in the peripheral blood via flow cytometry. In patients developing local or lymphogenic tumour relapse (n=4), we found an early significant increase in the concentration of tumour necrosis factor (TNF)-α as well as chemokine (C-C motif) ligand (CCL)-2 and CCL-4 compared to patients without relapse (n=4) and healthy donors (n=5). These changes were associated with an elevated activity of circulating MDSC indicated by an increased nitric oxide (NO) production in these cells. Elevated serum levels of TNF-α, CCL-2 and CCL-4 associated with an increased NO production in circulating MDSCs might be an early indicator of the incomplete RFA and subsequently a potential tumour relapse in NSCLC.

Prospective evaluation of follow-up in melanoma patients in Germany - results of a multicentre and longitudinal study.

BACKGROUND: Patient numbers requiring long-term melanoma surveillance are constantly rising. Surveillance is costly and guideline recommendations vary substantially. METHODS: In this German nationwide study, information on surveillance and treatment of patients diagnosed with melanoma and melanoma in situ (MMis) between April and June 2008 was prospectively collected over four years. Additionally, patient self-report questionnaires were evaluated to assess anxiety, depression, health-related quality of life, socio-demographic information and use of disease specific health information sources at year 4 after primary diagnosis. RESULTS: Complete data was available for 668 patients from 67 centres, of whom 96.0% were in regular melanoma surveillance. In year 3-4 of surveillance, only 55.6% of locoregionary metastases were detected during surveillance visits. Only 33.3% were self-detected by the patient even though 69.4% were documented as being clinically visible or palpable. Costs of 4year surveillance of 550 patients without tumour recurrence (stage I-IIC and MMis) accumulated to 228,155.75 €. Guideline-adherence for follow-up frequency, lymph node ultrasound, S100 serum level tests and diagnostic imaging recommendations was approximately 60% in year 3-4 of surveillance. Multivariate regression analysis showed that certain patient/tumour characteristics and regional differences were significantly associated with guideline deviations. The percentage of patients who exceeded published cut-off scores indicating clinically relevant symptoms of anxiety and depression were significantly increased. Patients frequently reported lack of psychosocial support and education but ascribed great importance to these. CONCLUSIONS: We recommend further reduction of melanoma follow-up in low-risk melanoma patients and improvement of psycho-social support and patient education for all melanoma patients.

A multicenter DeCOG study on predictors of vemurafenib therapy outcome in melanoma: pretreatment impacts survival.

BACKGROUND: Kinase inhibitors targeting the BRAF V600 mutation have become standard in the treatment of metastatic melanoma. Albeit in wide clinical use, the patterns associated with therapy outcome are not fully elucidated. The present study was aimed to identify predictive factors of therapy response and survival under the BRAF inhibitor vemurafenib. PATIENTS AND METHODS: This multicenter retrospective study analyzed patient, tumor, and pretreatment characteristics collected in BRAF V600-mutated stage IV melanoma patients before single-agent therapy with the BRAF inhibitor vemurafenib. RESULTS: A total of 300 patients from 14 centers were included into this study with a median follow-up time of 13.0 months. Median progression-free survival (PFS) was 5.1 months; median overall survival (OS) was 7.6 months. Best response under vemurafenib was associated with serum lactate dehydrogenase (LDH; ≤ versus >upper normal limit; P = 0.0000001), Eastern Cooperative Oncology Group (ECOG) overall performance status (OPS) (0 versus ≥ 1; P = 0.00089), and BRAF mutation subtype (V600E versus V600K; P = 0.016). Multivariate analysis identified ECOG OPS ≥ 1 [hazard ratio (HR) = 1.88; P = 0.00005], immunotherapy pretreatment (HR = 0.53; P = 0.0067), elevated serum LDH (HR = 1.45; P = 0.012), age >55 years (HR = 0.72; P = 0.019), and chemotherapy pretreatment (HR = 1.39; P = 0.036) as independent predictors of PFS. For OS, elevated serum LDH (HR = 1.99; P = 0.00012), ECOG OPS ≥ 1 (HR = 1.90; P = 0.00063), age >55 years (HR = 0.65; P = 0.011), kinase inhibitor pretreatment (HR = 1.86; P = 0.014), immunotherapy pretreatment (HR = 0.57; P = 0.025), chemotherapy pretreatment (HR = 2.17; P = 0.039), and male gender (HR = 0.70; 95% confidence interval 0.50-0.98; P = 0.039) were found as predictors. CONCLUSION: Our data demonstrate that the type of pretreatment strongly influences the outcome of vemurafenib therapy, with a precedent immunotherapy showing a positive, and a prior chemotherapy and kinase inhibitors showing a negative impact on survival, respectively. Moreover, we show that the patient's OPS, serum LDH, age, and gender independently impact vemurafenib therapy outcome. These findings should be taken into account for the future design of therapy sequencing in BRAF V600 mutation-positive melanoma patients.

Ultraviolet exposure and risk of melanoma and basal cell carcinoma in Ulm and Dresden, Germany.

BACKGROUND: There is a perpetuating increase in melanoma and basal cell carcinoma (BCC) incidence in Europe. Few studies are evaluating various risk factors for both tumours. OBJECTIVES: This pre-planned additional analysis directly compared occupational and past-time ultraviolet exposure behaviour, and examined the effects of sun sensitivity between melanoma and sporadic BCC, and assessed its importance for the two entities. PATIENTS/METHODS: The study included 503 patients (melanoma, n = 291 and BCC, n = 212), and 329 controls from Germany. In all, 244 (49%) of the cases and 165 (50%) of the controls were male (median age melanoma, 55 years; BCC, 69 years; and controls, 57 years). Selection of important risk factors was performed by backward elimination in a polytomous logistic regression. RESULTS: When directly comparing melanoma and sporadic BCC, actinic elastosis (OR 48.83; 95% CI 17.87, 133.40) and site were associated with a higher risk of melanoma, whereas mountaineering in childhood, sunburn 20 years before diagnosis, farming full time, sunbed use in general, seborrheic keratosis, actinic cheilitis, actinic keratosis and age were associated with a higher risk of sporadic BCC. Gardening 20 years before melanoma, hair colour and solar lentigo were risk factors for both entities. A re-evaluation of the data excluding lentiginous melanoma entities (i.e. acro-lentiginous and lentigo-maligna melanoma) resulted in selection of the same factors. However, compared to controls, atopy evolved as a protective factor for melanoma (OR 0.29; 95% CI 0.15, 0.57) and BCC (OR 0.41; 95% CI 0.17, 0.99), respectively, but was associated with a higher risk of sporadic BCC compared to melanoma. CONCLUSION: The odds for having clinical actinic elastosis was lower in BCC compared to melanoma. In contrast, various factors associated with chronic UV exposure and age had higher odds for sporadic BCC, rather than melanoma. Further research is required to set the context for these findings, especially regarding, atopy in non-lentiginous vs. lentiginous forms of melanoma, and possible molecular pathways involved.

Differential influence of vemurafenib and dabrafenib on patients' lymphocytes despite similar clinical efficacy in melanoma.

BACKGROUND: Since the majority of melanomas eventually become resistant and progress, combining selective BRAF inhibitors (BRAFi) with immunotherapies has been proposed to achieve more durable treatment responses. Here, we explored the impact of selective BRAFi on the hosts' immune system. PATIENTS AND METHODS: Clinical data, whole blood counts (WBC) and serum lactate dehydrogenase (LDH) of 277 vemurafenib- and 65 dabrafenib-treated melanoma patients were evaluated. The frequency and phenotype of lymphocyte subpopulations were determined by flow cytometry while T cell cytokine secretion was measured by multiplex assays. RESULTS: Progression-free survival (PFS) as well as overall survival (OS) were similar in patients treated with either BRAFi. High pretreatment LDH was associated with shorter PFS and OS in both groups. During therapy, peripheral lymphocytes decreased by 24.3% (median, P < 0.0001) in vemurafenib-treated patients but remained unchanged in dabrafenib-treated patients (+1.2%, P = 0.717). Differentiation of peripheral lymphocytes of vemurafenib-treated patients showed a significant decrease in CD4(+) T cells (P < 0.05). Within CD4(+) T cells obtained during treatment, an increase in CCR7(+)CD45RA(+) (naïve) and a decrease in CCR7(+)CD45RA(-) (central memory) populations were found (P < 0.01 for both). Furthermore, secretion of interferon-γ and interleukin-9 by CD4(+) T cells was significantly lower in samples obtained during vemurafenib treatment compared with baseline samples. CONCLUSION: While both compounds have comparable clinical efficacy, vemurafenib but not dabrafenib decreases patients peripheral lymphocyte counts and alters CD4(+) T cell phenotype and function. Thus, selective BRAFi can significantly affect patients' peripheral lymphocyte populations. Fully understanding these effects could be critical for successfully implementing combinatorial therapies of BRAFi with immunomodulatory agents.

The telomere profile distinguishes two classes of genetically distinct cutaneous squamous cell carcinomas.

The incidence of skin cancer is increasing worldwide and cutaneous squamous cell carcinomas (SCCs) are associated with considerable morbidity and mortality, particularly in immunosuppressed individuals ('carcinomatous catastrophy'). Yet, molecular mechanisms are still insufficiently understood. Besides ultraviolet (UV)-indicative mutations, chromosomal aberrations are prominent. As telomeres are essential in preserving chromosome integrity, and telomere erosion as well as aberrant spatial telomere distribution contribute to genomic instability, we first established telomere length profiles across the whole tissue and identified normal skin (10/30) harboring discrete epidermal sites (stem cell territories) of evenly short telomeres. Precancerous actinic keratoses (AKs) (17) and SCCs (27) expressed two telomere phenotypes: (i) tissue-wide evenly short to intermediate and (ii) longer and tissue-wide heterogeneous telomere lengths, suggesting two modes of initiation, with one likely to originate in the epidermal stem cells. Although tumor histotype, location, patient gender or age failed to distinguish the two SCC telomere phenotypes, as did telomerase activity, we found a trend for a higher degree of aberrant p53 and cyclin D1 expression with long/heterogeneous telomeres. In addition, we established an association for the short/homogeneous telomeres with a simpler and the heterogeneous telomeres with a more complex karyotype correlating also with distinct chromosomal changes. SCCs (13) from renal transplant recipients displayed the same telomere dichotomy, suggesting that both telomere subtypes contribute to 'carcinomatous catastrophy' under immunosuppression by selecting for a common set (3, 9p and 17q) and subtype-specific aberrations (e.g., 6p gain, 13q loss). As a second mechanism of telomere-dependent genomic instability, we investigated changes in telomere distribution with its most severe form of telomeric aggregates (TAs). We identified a telomere length-independent but progression-dependent increase in cells with small telomere associations in AKs (17/17) and additional TAs in SCCs (24/32), basal cell carcinomas (30/31) and malignant melanomas (15/15), and provide evidence for a reactive oxygen species-dependent mechanism in this UV-induced telomere organization-dependent genomic instability.

Cutaneous side effects of inhibitors of the RAS/RAF/MEK/ERK signalling pathway and their management.

Mutations in genes encoding for proteins along the RAS-RAF-MEK-ERK pathway have been detected in a variety of tumor entities, including malignant melanoma, thyroid, colonic and ovarian carcinomas, and some sarcomas. Thus, a number of inhibitors of this pathway have been developed, whose antitumor potential is currently being assessed in different clinical trials. Up to now one drug of this category (vemurafenib) has been approved by the FDA and the European Commission for late-stage melanoma. Although these new targeted anticancer therapies are generally considered to be safe and well tolerated, certain toxicities have been attributed to them, with cutaneous side effects being perhaps the most frequent amongst them. Based on results of clinical trials and on case series, a distinct profile of cutaneous toxicity has been observed, which is similar to that of EGFR and multikinase inhibitors. As exanthema, palmar-plantar erythrodysesthesia syndrome, hyperkeratosis, xerosis, pruritus, photosensitivity, and paronychia, can be controlled in most cases with common conservative modalities, special attention should be given to the early detection of epithelial skin tumors (mainly keratoakanthomas) that can be induced during therapy with these agents. This report reviews all current published data on cutaneous side effects of RAS-RAF-MEK-ERK pathway inhibitors, and attempts to provide the clinician with clear hints for their management.