Purpose Aggressive cutaneous squamous cell carcinoma (cSCC) is often a disfiguring and lethal disease. Very little is currently known about the mutations that drive aggressive cSCC. Experimental Design Whole exome sequencing was performed on 39 cases of aggressive cSCC to identify driver genes and novel therapeutic targets. Significantly mutated genes were identified with MutSig or complementary methods developed to specifically identify candidate tumor suppressors based upon their inactivating mutation bias. Results Despite the very high mutational background caused by UV exposure, 23 candidate drivers were identified including the well-known cancer-associated genes TP53, CDKN2A, NOTCH1, AJUBA, HRAS, CASP8, FAT1, and KMT2C (MLL3). Three novel candidate tumor suppressors with putative links to cancer or differentiation, NOTCH2, PARD3 and RASA1, were also identified as possible drivers in cSCC. KMT2C mutations were associated with poor outcome and increased bone invasion. Conclusions The mutational spectrum of cSCC is similar to that of head and neck squamous cell carcinoma and dominated by tumor suppressor genes. These results improve the foundation for understanding this disease and should aid in identifying and treating aggressive cSCC.

BACKGROUND: There is a need for improved prognostic markers in melanoma. In this study, the authors tested the prognostic significance and clinicopathologic correlations of v-raf murine sarcoma viral oncogene homolog B1 (BRAF) and neuroblastoma RAS viral (v-ras) oncogene homolog (NRAS) mutations in patients with metastatic melanoma. METHODS: Clinical and pathologic data were collected retrospectively on melanoma patients who were clinically tested for BRAF (exon 15) and NRAS (exons 1 and 2) mutations at The University of Texas M. D. Anderson Cancer Center. Analyses were performed to identify significant associations of mutations with tumor and patient characteristics and with survival from the diagnosis of stage IV disease. RESULTS: The genotypes of the full cohort (n ¼ 677) were 47% BRAF mutation, 20% NRAS mutation, and 32% wild-type for BRAF and NRAS (''WT''). Tumor mutation status was associated (P ¼ .008) with the risk of central nervous system involvement at the diagnosis of stage IV disease, with a higher prevalence observed in BRAF-mutant (24%) and NRAS-mutant (23%) patients than in WT patients (12%). Among patients with nonuveal melanoma who underwent mutation testing within 6 months of stage IV diagnosis (n ¼ 313), patients with NRAS mutations had a median survival of 8.2 months from stage IV diagnosis, which was shorter than the median survival of WT patients (15.1 months; P ¼ .004). Multivariate analysis of this population incorporating age, sex, metastases (M1) category, serum lactate dehydrogenase level, and mutation status confirmed that NRAS mutations are associated independently with decreased overall survival (vs WT; P ¼ .005; hazard ratio, 2.05). CONCLUSIONS: Patients with BRAF or NRAS mutations were more likely than WT patients to have central nervous system involvement at the time they were diagnosed with distant metastatic disease. NRAS mutation status was identified as an independent predictor of shorter survival after a diagnosis of stage IV melanoma. Cancer 2012;118:4014-

Immunomodulatory drugs that leverages host immune mechanisms to destroy tumor cells have been met with great promise in the treatment of cancer. Immunotherapy, targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and the programmed cell death 1 (PD-1) receptor and its ligand (PD-L1) have shown tremendous improvements in the survival of patients with advanced solid tumors. However, the development of dermatologic toxicity (DT) is a consequence to immunotherapy. Review of published reports of the DT to immunotherapy revealed patients receiving anti-CTCLA-4 antibody or anti-PD-1/PD-L1 antibody often develop a DT of any type and grade. In this article, of the 3825 patients who were treated with anti-PD-1 and of 556 patients receiving anti-PD-L1, DT of any type and grade were reported in 1474 (∼39%) and 95 (∼17%) of patients, respectively. The emergence of specific types of DT to immunotherapy is beginning to be recognized can be categorized into four groups: (a) inflammatory, (b) immunobullous, (c) alteration of keratinocytes and (d) alteration of melanocytes. Lichenoid dermatitis and bullous pemphigoid appear to be DT more associated with anti-PD-1/PD-L1 antibody. The DT profile in patients receiving immunotherapy is diverse, and early recognition of specific types of DT that clinicians may encounter is critical for optimal patient careKeywords: anti-CTLA-4, anti-PD-1, anti-PD-L1, dermatologic toxicities, immune checkpoint antibody Curry JL, Tetzlaff MT, Nagarajan P, Drucker C, Diab A, Hymes SR, Duvic M, Hwu W-J, Wargo JA, Torres-Cabala CA, Rapini RP, Prieto VG. Diverse types of dermatologic toxicities from immune checkpoint blockade therapy. J Cutan Pathol 2017; 44: 158-176.

Recent studies have implicated interferon signaling in the regulation of cellular senescence. However, the role of specific interferon-inducible proteins in cellular senescence remains to be defined. Here we report that IFI 16, an interferon-inducible transcriptional modulator from the p200-protein family, contributes to cellular senescence of prostate epithelial cells. Normal human prostate epithelial cells (PrEC) in culture expressed detectable levels of IFI 16, and the levels increased more than fourfold when cells approached cellular senescence. Consistent with a role of IFI 16 in cellular senescence, human prostate cancer cell lines either did not express IFI 16 or expressed a variant form, which was primarily detected in the cytoplasm of prostate cancer cells and not in the nucleus. Moreover, overexpression of functional IFI 16 in human prostate cancer cell lines inhibited colony formation. Additionally, ectopic expression of IFI 16 in clonal prostate cancer cell lines was associated with a senescence-like phenotype, production of senescence-associated b-galactosidase (a biochemical marker for cellular senescence), and reduction of S-phase cells in culture. Importantly, upregulation of p21 WAF1 and inhibition of E2F-stimulated transcription accompanied inhibition of cell growth by IFI 16 in prostate cancer cell lines. Collectively, our observations support the idea that increased levels of IFI 16 in PrECs contribute to senescence-associated irreversible cell growth arrest.

Monoclonal antibodies against the immune checkpoint programmed cell death receptor 1 (PD-1) improve the hosts' antitumor immune response and have showed tremendous promise in the treatment of advanced solid tumors and hematologic malignancies. Reports of serious autoimmune dermatologic toxicities from immune checkpoint blockade therapy, however, are emerging. We report our experience with five patients who presented with pruritic vesicles and blisters on the skin while treated with anti-PD-1 antibody immunotherapy with either nivolumab or pembrolizumab. Four of the patients' skin biopsies revealed subepidermal bullae with immunohistochemical study for type IV collagen labeling the floor of the blister cavity and direct immunofluorescence studies (in three of the four patients tested) decorated linear IgG and C3 immune deposits on the blister roof, diagnostic of bullous pemphigoid. One patient developed bullous erythema multiforme. All patients had partial or complete resolution of skin lesions following treatment with systemic corticosteroid and cessation of checkpoint blockade. Recognition and treatment of rare immune-related bullous dermatologic toxicities will become increasingly important as more patients are treated with effective and newer immune checkpoint blockade therapy.

Immunotherapy targeting the programmed cell death 1 (PD-1) receptor has demonstrated tremendous promise in the treatment of advanced solid tumors. Dermatologic toxicities, however, are an emerging consequence of this therapy and have been clearly associated with immune checkpoint blockade antibodies. Distinctive clinical and histologic subtypes of dermatologic toxicity secondary to immunotherapy are emerging and include rare autoimmune bullous reactions (eg, bullous pemphigoid) and lichenoid eruptions. We report three patients who developed lichenoid dermatitis while receiving anti-PD-1 antibody therapy. The mean time to onset of lichenoid dermatologic toxicity was 42 days (range: 1-75 days) from initiation of anti-PD-1 antibody therapy. Lesions most frequently presented on the extremities and trunk as pustules, papules, and plaques. The face was not commonly involved. Of the five skin biopsies examined, all demonstrated dense band-like lymphocytic infiltrate, hyperkeratosis, hypergranulosis, saw-tooth rete ridge pattern, and dyskeratosis. Acanthosis was a feature in all of the skin biopsies, and in one, epidermal hyperplasia was prominent. In several skin biopsies, histologic features supporting a lichenoid drug eruption were present, including parakeratosis, spongiosis, periadnexal/perivascular inflammation, and eosinophils. Furthermore, the histologic features varied in skin biopsy specimens taken from the same patient at different sites, supporting a drug reaction. All patients' skin lesions improved with use of steroids: two were treated with topical steroids and one with systemic steroids. Recognition of the histopathologic patterns of dermatologic toxicities resulting from immune checkpoint blockade therapy will become increasingly important for ensuring appropriate management of dermatologic toxicities and optimal patient care.

Purpose Merkel cell carcinoma (MCC) is an aggressive cancer with frequent metastasis and death with few effective therapies. Because programmed death ligand-1 (PD-L1) is frequently expressed in MCC, immune checkpoint blockade has been leveraged as treatment for metastatic disease. There is therefore a critical need to understand the relationships between MCPyV status, immune profiles, and patient outcomes. Experimental Design IHC for CD3, CD8, PD-1, PD-L1, and MCPyV T-antigen (to determine MCPyV status) was performed on 62 primary MCCs with annotated clinical outcomes. Automated image analysis quantified immune cell density (positive cells/mm2) at discrete geographic locations (tumor periphery, center, and hotspot). T-cell receptor sequencing (TCRseq) was performed in a subset of MCCs. Results No histopathologic variable associated with overall survival (OS) or disease-specific survival (DSS), whereas higher CD3+ (P = 0.004) and CD8+ (P = 0.037) T-cell density at the tumor periphery associated with improved OS. Higher CD8+ T-cell density at the tumor periphery associated with improved DSS (P = 0.049). Stratifying MCCs according to MCPyV status, higher CD3+ (P = 0.026) and CD8+ (P = 0.015) T-cell density at the tumor periphery associated with improved OS for MCPyV+ but not MCPyV− MCC. TCRseq revealed clonal overlap among MCPyV+ samples, suggesting an antigen-specific response against a unifying antigen. Conclusions These findings establish the tumor-associated immune infiltrate at the tumor periphery as a robust prognostic indicator in MCC and provide a mechanistic rationale to further examine whether the immune infiltrate at the tumor periphery is relevant as a biomarker for response in ongoing and future checkpoint inhibitor trials in MCC.

BACKGROUND: Hotspot mutations in BRAF and NRAS are the most common somatic events in patients with melanoma. These mutations occur at highly conserved residues, but include several different substitutions. To determine whether specific mutations are clinically important to differentiate, tumor characteristics and clinical outcomes were compared among patients with advanced melanoma with 1) BRAF V600E versus V600K mutations and 2) NRAS exon 1 versus exon 2 mutations. METHODS: Retrospective clinical and pathologic data were collected for patients with advanced melanoma with BRAF or NRAS mutations. The demographics, tumor characteristics, and clinical outcomes of the patients were compared to identify significant mutation-specific associations. RESULTS: Among 302 patients with activating BRAF mutations, 76% had BRAF V600E and 24% had V600K substitutions. Compared with V600E, the presence of a V600K mutation was significantly associated with older age (median, 60.0 years vs 44.7 years; P <.001), male sex (80% vs 59%; P 5.001), head=neck primary tumor location (30% vs 15%; P 5.0026), shorter interval to stage IV disease (0.98 years vs 2.8 years; P 5.015), and a shorter overall survival from the time of diagnosis of stage IV disease (median, 2.44 years vs 1.25 years; hazards ratio, 1.68 [P 5.014]). Comparison of 136 patients with NRAS exon 1 (18%) and exon 2 (82%) mutations found an association with primary tumor histology (P 5.0096) only. CONCLUSIONS: The presence of different substitutions at BRAF V600 correlates with patient demographics, tumor characteristics, and prognosis. These findings demonstrate the presence of mutation-specific clinical differences between different BRAF genotypes in patients with melanoma, and support the incorporation of this information in patient evaluation and clinical trial design. Cancer 2013;119:3821-9.