In mice and humans, binding of alpha-melanocyte--stimulating hormone to the melanocyte-stimulating--hormone receptor (MSHR), the protein product of melanocortin-1 receptor (MC1R) gene, leads to the synthesis of eumelanin. In the mouse, ligation of MSHR by agouti signaling protein (ASP) results in the production of pheomelanin. The role of ASP in humans is unclear. We sought to characterize the agouti signaling protein gene (ASIP) in a group of white subjects, to assess whether ASIP was a determinant of human pigmentation and whether this gene may be associated with increased melanoma risk. We found no evidence of coding-region sequence variation in ASIP, but detected a g.8818A-->G polymorphism in the 3' untranslated region. We genotyped 746 participants in a study of melanoma susceptibility for g.8818A-->G, by means of polymerase chain reaction and restriction fragment--length polymorphism analysis. Among the 147 healthy controls, the frequency of the G allele was.12. Carriage of the G allele was significantly associated with dark hair (odds ratio 1.8; 95% confidence interval [CI] 1.2--2.8) and brown eyes (odds ratio 1.9; 95% CI 1.3--2.8) after adjusting for age, gender, and disease status. ASIP g.8818A-->G was not associated independently with disease status. This is the first report of an association of ASIP with specific human pigmentation characteristics. It remains to be investigated whether the interaction of MC1R and ASIP can enhance prediction of human pigmentation and melanoma risk.

BACKGROUND Incidence of cutaneous melanoma continues to increase in the Caucasian population worldwide. Approximately 5% of melanoma patients develop additional primary melanoma. This rate is significantly higher than the estimated lifetime risk of an individual for developing the disease (1.4%). These features suggest that a genetic predisposition may underlie multiple primary melanomas (MPMs). Prior studies had identified CDKN2A mutations in a few MPM individuals. The objectives of this study were to determine the frequency of family history of melanoma in MPM cases, to characterize other clinical features including history of other cancer, and to determine the association with functional CDKN2A mutations. METHODS This study used a case series design. All living patients who had been seen in the Pigmented Lesion Clinic at the University of Pennsylvania and who had more than one primary invasive malignant melanoma or an invasive primary followed by an in situ melanoma were eligible for participation. RESULTS Individuals with MPM frequently had a family history of melanoma, dysplastic nevi (DN), and/or another cancer including basal cell carcinoma (BCC), and squamous cell carcinoma breast cancer, and a personal history of DN, and basal cell carcinoma. Germline mutations in CDKN2A gene were identified in 8 of 96 MPM cases (8.3%, 95% confidence interval, 6.7–9.9%). CONCLUSIONS These data indicate that the presence of MPM is associated with a modest incidence of a family history of melanoma, DN, or BCC and a small association with CDKN2A mutations. Therefore, in addition to the MPM index case, other family members can benefit from screening and regular surveillance for melanoma, DN, and BCC. Cancer 2002;94:2248–55. © 2002 American Cancer Society. DOI 10.1002/cncr.10454

The melanocortin-1 receptor gene (MC1R) encodes a membrane-bound receptor protein that is central to melanin synthesis. The coding region of MC1R is highly polymorphic and associations of variants with pigmentation phenotypes and risk for cutaneous neoplasms have been reported. We sought to determine the distribution and frequency of MC1R variants and their relationship to pigmentation characteristics in 179 Caucasian controls from the United States. One hundred thirty-five (75.4%) subjects carried one or more variants, and we determined that carriage of the previously designated “red hair color” (RHC) alleles, R151C, R160W, and D294H was strongly associated with fair pigmentation phenotypes including light hair and eye color, tendency to burn, decreased tendency to tan, and freckling. We used SIFT software to define MC1R protein positions that were predicted intolerant to amino acid substitutions; detected variants that corresponded to intolerant substitutions were D84E, R142H, R151C, I155T, R160W, and D294H. Carriage of one or more of these putative functionally important variants or the frameshift variant ins86A was significantly associated with fair pigmentation phenotypes. Analyses limited to carriage of ins86A and the three non-RHC alleles identified by SIFT were attenuated and no longer reached statistical significance. This is the first study to describe MC1R variants among control subjects from the U.S. Our results indicate that the frequency of variants is similar to that previously observed among non-U.S. Caucasians. Risk variants defined by either the published literature or by evolutionary criteria are strongly and significantly associated with all fair pigmentation phenotypes that were measured.

Circulating IL-6, an activator of JAK/STAT signaling, is associated with poor prognosis and aromatase inhibitor (AI) resistance in hormone-receptor positive (HR+) breast cancer. Here we report the results of a phase 2 single-arm Simon 2-stage trial combining Ruxolitinib, an oral selective inhibitor of JAK1/2, with exemestane, a steroidal AI, in patients with HR+ metastatic breast cancer (MBC) after progression on non-steroidal AI (NSAI). Safety and efficacy were primary objectives, and analysis of inflammatory markers as predictors of response was a key secondary objective. Twenty-five subjects enrolled. The combination of ruxolitinib and exemestane was safe, though anemia requiring transfusion in 5/15 (33%) at the 25 mg dose in stage 1 led to a reduction to 15 mg twice daily in stage 2 (with no additional transfusions). Clinical benefit rate (CBR) in the overall study population was 24% (95% CI 9.4–45.1); 6/25 patients demonstrated stable disease for ≥6 months. Median progression-free survival was 2.8 months (95% CI 2.6–3.9). Exploratory biomarkers revealed high levels of systemic inflammation and 60% harbored a high-risk IL-6 genotype. Pharmacodynamics demonstrated modest on-target inhibition of phosphorylated-STAT3 by ruxolitinib at a tolerable dose. Thus, ruxolitinib combined with exemestane at a tolerable dose was safe but minimally active in AI-resistant tumors of patients with high levels of systemic inflammation. These findings highlight the need for more potent and specific therapies targeting inflammation in MBC.

Resistance to aromatase inhibitors in ER+ breast cancer leads to recurrence and progression in the metastatic setting. JAK/STAT pathway activation is a resistance mechanism that could potentially be overcome with the use of JAK inhibitor therapy. Methods: We performed a phase II trial of exemestane, 25 mg daily, and ruxolitinib, 25 mg BID, in postmenopausal women with advanced, ER+ breast cancer who had progressed on a non-steroidal aromatase inhibitor and had either measureable or bone-only disease. A Simon 2-stage design was employed. A “go” decision to second stage would occur if fewer than 5/15 patients experienced any grade 3/4 toxicity requiring discontinuation from the study within the first treatment cycle. Results: Fifteen patients were enrolled; during cycle 1, no patient discontinued for toxicity and 1 patient went off study for progression of bone disease. 36 grade 3 events occurred; anemia was most common (n = 5), requiring transfusion in all patients. 47% required dose reduction. No partial or complete responses occurred; 3/15 (20%) had stable disease ≥6 months (clinical benefit, CB). Baseline CRP ≥8 was significantly associated with CB (3/3 CB vs. 1/11 non-CB; p = 0.011); other markers, including baseline ESR, IL-6 genotype status and primary tumor phosphoSTAT3 expression were not associated with CB in this small sample, though high tumoral pSTAT3 was seen in 66% of CB and 33% of non-CB. A novel pharmacodynamic (PD) assay to assess STAT3 phosphorylation in peripheral blood mononuclear cells after ruxolitinib exposure demonstrated differential effects in patients with CB vs. those without CB. Conclusions: The combination of exemestane and the JAK2 inhibitor ruxolitinib met safety criteria for continued enrollment. Anemia, an expected toxicity of R, was common and the high rate of severe anemia and need for dose reductions has led to a decision to reduce the starting dose of ruxolitinib to 15 mg BID moving forward. Promising predictive markers, including CRP, tumor pSTAT3 and a novel PD assay for pSTAT3 will be further evaluated. Citation Format: Angela M. DeMichele, Christopher B. Colameco, Anna Kalota, Andrea B. Troxel, Robin Holmes, Rebecca Cimildoro, Kelly Zafman, Kevin R. Fox, Susan M. Domchek, Keerthi Gogineni, Angela R. Bradbury, Jennifer M. Matro, Natalie Shih, Michael D. Feldman, Amy S. Clark, Elizabeth O. Hexner, Jacqueline F. Bromberg. A phase II trial of exemestane and ruxolitinib for aI-resistant ER+ breast cancer: Interim safety, efficacy, and biomarker analysis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT114. doi:10.1158/1538-7445.AM2015-CT114