Sarah T. Arron

Efficacy and Safety of Vismodegib in Advanced Basal-Cell Carcinoma

BACKGROUND Alterations in hedgehog signaling are implicated in the pathogenesis of basal-cell carcinoma. Although most basal-cell carcinomas are treated surgically, no effective therapy exists for locally advanced or metastatic basal-cell carcinoma. A phase 1 study of vismodegib (GDC-0449), a first-in-class, small-molecule inhibitor of the hedgehog pathway, showed a 58% response rate among patients with advanced basal-cell carcinoma. METHODS In this multicenter, international, two-cohort, nonrandomized study, we enrolled patients with metastatic basal-cell carcinoma and those with locally advanced basal-cell carcinoma who had inoperable disease or for whom surgery was inappropriate (because of multiple recurrences and a low likelihood of surgical cure, or substantial anticipated disfigurement). All patients received 150 mg of oral vismodegib daily. The primary end point was the independently assessed objective response rate; the primary hypotheses were that the response rate would be greater than 20% for patients with locally advanced basal-cell carcinoma and greater than 10% for those with metastatic basal-cell carcinoma. RESULTS In 33 patients with metastatic basal-cell carcinoma, the independently assessed response rate was 30% (95% confidence interval [CI], 16 to 48; P=0.001). In 63 patients with locally advanced basal-cell carcinoma, the independently assessed response rate was 43% (95% CI, 31 to 56; P<0.001), with complete responses in 13 patients (21%). The median duration of response was 7.6 months in both cohorts. Adverse events occurring in more than 30% of patients were muscle spasms, alopecia, dysgeusia (taste disturbance), weight loss, and fatigue. Serious adverse events were reported in 25% of patients; seven deaths due to adverse events were noted. CONCLUSIONS Vismodegib is associated with tumor responses in patients with locally advanced or metastatic basal-cell carcinoma. (Funded by Genentech; Erivance BCC ClinicalTrials.gov number, NCT00833417.).

Loss-of-function mutations in Notch receptors in cutaneous and lung squamous cell carcinoma

Squamous cell carcinomas (SCCs) are one of the most frequent forms of human malignancy, but, other than TP53 mutations, few causative somatic aberrations have been identified. We identified NOTCH1 or NOTCH2 mutations in ∼75% of cutaneous SCCs and in a lesser fraction of lung SCCs, defining a spectrum for the most prevalent tumor suppressor specific to these epithelial malignancies. Notch receptors normally transduce signals in response to ligands on neighboring cells, regulating metazoan lineage selection and developmental patterning. Our findings therefore illustrate a central role for disruption of microenvironmental communication in cancer progression. NOTCH aberrations include frameshift and nonsense mutations leading to receptor truncations as well as point substitutions in key functional domains that abrogate signaling in cell-based assays. Oncogenic gain-of-function mutations in NOTCH1 commonly occur in human T-cell lymphoblastic leukemia/lymphoma and B-cell chronic lymphocytic leukemia. The bifunctional role of Notch in human cancer thus emphasizes the context dependency of signaling outcomes and suggests that targeted inhibition of the Notch pathway may induce squamous epithelial malignancies.

Chronic phototoxicity and aggressive squamous cell carcinoma of the skin in children and adults during treatment with voriconazole

BACKGROUND Voriconazole is a broad-spectrum antifungal agent associated with photosensitivity and accelerated photoaging. A possible link with aggressive squamous cell carcinoma (SCC) has also been reported. OBJECTIVE We sought to determine the incidence and frequency of cutaneous SCC among patients undergoing long-term treatment with voriconazole who also manifest features of chronic phototoxicity. METHODS We conducted a retrospective review of patients who developed one or more squamous cell neoplasms during long-term treatment with voriconazole at 3 academic dermatology centers. RESULTS A total of 51 cutaneous SCC were identified in 8 patients (median age 34.5 years, range 9-54) treated with chronic voriconazole (median duration 46.5 months, range 13-60). Underlying diagnoses included graft-versus-host disease, HIV, and Wegener granulomatosis. Signs of chronic phototoxicity and accelerated photoaging included erythema, actinic keratoses, and lentigo formation. LIMITATIONS The retrospective nature of the study cannot determine the true population risk of SCC associated with voriconazole therapy. A prospective cohort study is needed. CONCLUSION A high index of suspicion for photosensitivity and SCC may be warranted with chronic voriconazole use when used in the setting of concurrent immunosuppression.

Temporal Dissection of Tumorigenesis in Primary Cancers

Timely intervention for cancer requires knowledge of its earliest genetic aberrations. Sequencing of tumors and their metastases reveals numerous abnormalities occurring late in progression. A means to temporally order aberrations in a single cancer, rather than inferring them from serially acquired samples, would define changes preceding even clinically evident disease. We integrate DNA sequence and copy number information to reconstruct the order of abnormalities as individual tumors evolve for 2 separate cancer types. We detect vast, unreported expansion of simple mutations sharply demarcated by recombinative loss of the second copy of TP53 in cutaneous squamous cell carcinomas (cSCC) and serous ovarian adenocarcinomas, in the former surpassing 50 mutations per megabase. In cSCCs, we also report diverse secondary mutations in known and novel oncogenic pathways, illustrating how such expanded mutagenesis directly promotes malignant progression. These results reframe paradigms in which TP53 mutation is required later, to bypass senescence induced by driver oncogenes.

Memory regulatory T cells reside in human skin.

Regulatory T cells (Tregs), which are characterized by expression of the transcription factor Foxp3, are a dynamic and heterogeneous population of cells that control immune responses and prevent autoimmunity. We recently identified a subset of Tregs in murine skin with properties typical of memory cells and defined this population as memory Tregs (mTregs). Due to the importance of these cells in regulating tissue inflammation in mice, we analyzed this cell population in humans and found that almost all Tregs in normal skin had an activated memory phenotype. Compared with mTregs in peripheral blood, cutaneous mTregs had unique cell surface marker expression and cytokine production. In normal human skin, mTregs preferentially localized to hair follicles and were more abundant in skin with high hair density. Sequence comparison of TCRs from conventional memory T helper cells and mTregs isolated from skin revealed little homology between the two cell populations, suggesting that they recognize different antigens. Under steady-state conditions, mTregs were nonmigratory and relatively unresponsive; however, in inflamed skin from psoriasis patients, mTregs expanded, were highly proliferative, and produced low levels of IL-17. Taken together, these results identify a subset of Tregs that stably resides in human skin and suggest that these cells are qualitatively defective in inflammatory skin disease.

NOTCH1 Mutations Occur Early during Cutaneous Squamous Cell Carcinogenesis

Cutaneous SCC (cSCC) is the most frequent skin cancer with metastatic potential and can manifest rapidly as a common side effect in patients receiving systemic kinase inhibitors. Here we use massively parallel exome and targeted level sequencing 132 sporadic cSCC, 39 squamoproliferative lesions and cSCC arising in patients receiving the BRAF inhibitor vemurafenib, as well as 10 normal skin samples to identify significant NOTCH1 mutation as an early event in squamous cell carcinogenesis. Bisected vemurafenib induced lesions revealed surprising heterogeneity with different activating HRAS and NOTCH1 mutations identified in two halves of the same cSCC suggesting polyclonal origin. Immunohistochemical analysis using an antibody specific to nuclear NOTCH1 correlates with mutation status in sporadic cSCC and regions of NOTCH1 loss or down-regulation are frequently observed in normal looking skin. Our data indicate that NOTCH1 acts as a gatekeeper in human cSCC.

Transcriptome Sequencing Demonstrates that Human Papillomavirus Is Not Active in Cutaneous Squamous Cell Carcinoma

Beta-papillomavirus (β-HPV) DNA is present in some cutaneous squamous cell carcinomas (cuSCC), but no mechanism of carcinogenesis has been determined. We used ultra-high throughput sequencing of the cancer transcriptome to assess whether papillomavirus transcripts are present in these cancers. Sixty-seven cuSCC samples were assayed for β-HPV DNA by PCR, and viral loads were measured with type-specific qPCR. Thirty-one SCCs were selected for whole transcriptome sequencing. Transcriptome libraries were prepared in parallel from the HPV18 positive HeLa cervical cancer cell line and HPV16 positive primary cervical and periungual SCC. Thirty percent (20/67) of the tumors were positive for β-HPV DNA, but there was no difference in β-HPV viral load between tumor and normal tissue (p=0.310). Immunosuppression and age were significantly associated with higher viral load (p=0.016 for immunosuppression; p=0.0004 for age). Transcriptome sequencing failed to identify papillomavirus expression in any of the skin tumors. In contrast, HPV 16 and 18 mRNA transcripts were readily identified in primary cervical and periungual cancers and HeLa cells. These data demonstrate that papillomavirus mRNA expression is not a factor in the maintenance of cuSCC.

High Cumulative Dose Exposure to Voriconazole is Associated with Cutaneous Squamous Cell Carcinoma in Lung Transplant Recipients

BACKGROUND Lung transplant recipients (LTR) have an increased risk of cutaneous squamous cell carcinoma (SCC) due to immunosuppressive therapy. Voriconazole, which is associated with phototoxic side effects in some patients, may be an additional risk factor for SCC in this population. METHODS To test whether voriconazole is a risk factor for developing SCC in LTR, we evaluated cumulative exposure to voriconazole in 327 adults who underwent lung transplantation at one center between 1991 and 2010. Voriconazole exposure was assessed as a time-varying covariate. We used survival analysis methods to assess the risk of developing SCC over time. RESULTS Exposure to voriconazole was associated with a 2.6-fold increased risk for SCC. This phenomenon was dose-dependent: the risk for SCC increased by 5.6% with each 60-day exposure at a standard dose of 200 mg twice daily. At 5 years after transplant, voriconazole conferred an absolute risk increase for SCC of 28%. CONCLUSIONS These results suggest that caution should be taken when using voriconazole in LTR because this drug increases the already high risk for SCC in this population.

Pivotal ERIVANCE basal cell carcinoma (BCC) study: 12-month update of efficacy and safety of vismodegib in advanced BCC

BACKGROUND Primary analysis from the pivotal ERIVANCE BCC study resulted in approval of vismodegib, a Hedgehog pathway inhibitor indicated for treatment of adults with metastatic or locally advanced basal cell carcinoma (BCC) that has recurred after surgery or for patients who are not candidates for surgery or radiation. OBJECTIVE An efficacy and safety analysis was conducted 12 months after primary analysis. METHODS This was a multinational, multicenter, nonrandomized, 2-cohort study in patients with measurable and histologically confirmed locally advanced or metastatic BCC taking oral vismodegib (150 mg/d). Primary outcome measure was objective response rate (complete and partial responses) assessed by independent review facility. RESULTS After 12 months of additional follow-up, median duration of exposure to vismodegib was 12.9 months. Objective response rate increased from 30.3% to 33.3% in patients with metastatic disease, and from 42.9% to 47.6% in patients with the locally advanced form. Median duration of response in patients with locally advanced BCC increased from 7.6 to 9.5 months. No new safety signals emerged with extended treatment duration. LIMITATIONS Limitations include low prevalence of advanced BCC and challenges of designing a study with heterogenous manifestations. CONCLUSION The 12-month update of the study confirms the efficacy and safety of vismodegib in management of advanced BCC.

Cutaneous squamous cell carcinoma and human papillomavirus: is there an association?

BACKGROUND The role of human papillomavirus (HPV) in the induction and maintenance of cervical, anogenital, and some oropharyngeal carcinomas is well recognized, but its role in cutaneous squamous cell carcinoma (SCC) remains to be elucidated. HPV is thought to act as a possible cocarcinogen in the development of SCC. OBJECTIVE To review the literature assessing the correlation between and possible causation of HPV and cutaneous SCC in immunocompetent and immunocompromised populations. METHODS We reviewed HPV sampling and detection methods, epidemiologic studies examining HPV carriage in immunocompetent and immunosuppressed individuals, and evidence asserting an association between HPV and cutaneous SCC. RESULTS Although an abundant body of evidence points toward a link between HPV and cutaneous SCC, many studies indicate otherwise. Recent studies have focused on viral activity in addition to DNA presence. CONCLUSION The possibility exists that HPV may play a role in the induction but not maintenance of cutaneous SCC.