Background

Melanoma of unknown primary (MUP) represents a poorly understood group of patients both clinically and immunologically. We investigated differences in prognosis and candidate immune biomarkers in patients with unknown compared with those with known primary melanoma enrolled in the E1609 adjuvant trial that tested ipilimumab at 3 and 10 mg/kg vs high-dose interferon-alfa (HDI).

Patients and methods

MUP status was defined as initial presentation with cutaneous, nodal or distant metastasis without a known primary. Relapse-free survival (RFS) and overall survival (OS) rates were estimated by the Kaplan-Meier method. Stratified (by stage) log-rank test was used to compare RFS and OS by primary tumor status. Gene expression profiling (GEP) was performed on the tumor biopsies of a subset of patients. Similarly, peripheral blood samples were tested for candidate soluble and cellular immune biomarkers.

Results

MUP cases represented 12.8% of the total population (N=1699) including 11.7% on the ipilimumab arms and 14.7% on the HDI arm. Stratifying by stage, RFS (p=0.001) and overall survival (OS) (p=0.009) showed outcomes significantly better for patients with unknown primary. The primary tumor status remained prognostically significant after adjusting for treatment and stage in multivariate Cox proportional hazards models. Including only ipilimumab-treated patients, RFS (p=0.005) and OS (p=0.023) were significantly better in favor of those with unknown primary. Among patients with GEP data (n=718; 102 MUP, 616 known), GEP identified pathways and genes related to autoimmunity, inflammation, immune cell infiltration and immune activation that were significantly enriched in the MUP tumors compared with known primaries. Further investigation into infiltrating immune cell types estimated significant enrichment with CD8 +and CD4+T cells, B cells and NK cells as well as significantly higher major histocompatibility complex (MHC)-I and MHC-II scores in MUP compared with known primary. Among patients tested for circulating biomarkers (n=321; 66 unknown and 255 known), patients with MUP had significantly higher circulating levels of IL-2R (p=0.04).

Conclusion

Patients with MUP and high-risk melanoma had significantly better prognosis and evidence of significantly enhanced immune activation within the TME and the circulation, supporting the designation of MUP as a distinct prognostic marker in patients with high-risk melanoma.

Background

CTLA4-blocking antibodies induce tumor regression in a subset of patients with melanoma. Analysis of immune parameters in peripheral blood may help define how responses are mediated.

Methods

Peripheral blood from HLA-A*0201-positive patients with advanced melanoma receiving tremelimumab (formerly CP-675,206) at 10 mg/kg monthly was repeatedly sampled during the first 4 cycles. Samples were analyzed by 1) tetramer and ELISPOT assays for reactivity to CMV, EBV, MART1, gp100, and tyrosinase; 2) activation HLA-DR and memory CD45RO markers on CD4+/CD8+ cells; and 3) real-time quantitative PCR of mRNA for FoxP3 transcription factor, preferentially expressed by T regulatory cells. The primary endpoint was difference in MART1-specific T cells by tetramer assay. Immunological data were explored for significant trends using clustering analysis.

Results

Three of 12 patients eligible for immune monitoring had tumor regression lasting > 2 years without relapse. There was no significant change in percent of MART1-specific T cells by tetramer assay. Additionally, there was no generalized trend toward postdosing changes in other antigen-specific CD8+ cell populations, FoxP3 transcripts, or overall changes in surface expression of T-cell activation or memory markers. Unsupervised hierarchical clustering based on immune monitoring data segregated patients randomly. However, clustering according to T-cell activation or memory markers separated patients with clinical response and most patients with inflammatory toxicity into a common subgroup.

Conclusion

Administration of CTLA4-blocking antibody tremelimumab to patients with advanced melanoma results in a subset of patients with long-lived tumor responses. T-cell activation and memory markers served as the only readout of the pharmacodynamic effects of this antibody in peripheral blood.

Clinical trial registration number

NCT00086489.

Rose Bengal (RB) is a red synthetic dye that was initially used in the garment industry and has been used safely for decades as a corneal stain by ophthalmologists. Antineoplastic properties of RB have also been observed, though the mechanism of action remained to be elucidated. Recently, interest in RB as a therapeutic cancer treatment has increased due to significant anti-tumor responses with direct tumor injection in human clinical trials for metastatic melanoma. In these patients, there has been the implication that RB may mount a T-cell mediated anti-tumor response and impart antigen-specific responses in distant bystander lesions. This article serves to evaluate the potential of intralesional rose bengal to stimulate T-cell mediated anti-tumor responses in in-vitro, pre-clinical, and clinical studies.

Tumor necrosis factor-alpha (TNF-alpha) is an immunomodulatory cytokine that has exhibited anti-tumor activity in a variety of experimental systems. However, the toxicities associated with systemic administration of TNF-alpha have limited its clinical utility and have led to the investigation of targeted delivery techniques with the ability to present the TNF-alpha dose directly to the vascular bed of the tumor. The intra-arterial (IA) administration of TNF-alpha to patients with liver metastases represents one such approach, and recent work suggests that subsequent ablation of the tumor's arterial supply via embolization may enhance the efficacy of intra-arterial treatments (hepatic chemoembolization). The present study was undertaken to test the hypothesis that IA administration of TNF-alpha is superior to the intravenous (IV) route for inhibition of tumor growth in a regionally confined rat mammary adenocarcinoma model that provides for ablation of the arterial supply to the tumor following cytokine therapy. Rats bearing hind limb mammary adenocarcinomas received single IA or IV infusions of 8 x 10(5), 1 x 10(6), and 1.5 x 10(6) units of TNF-alpha via the common femoral artery (CFA) followed 1 h later by ligation of the artery. Control animals received either no treatment or IA infusion of 2% normal rat serum (NRS) followed by ipsilateral CFA ligation. Tumor size was measured every other day after treatment. Tumor growth inhibition occurred in the first 5 to 10 days after treatment. IV administration of TNF-alpha did not result in visual tumor necrosis or significant reduction in the rate of tumor growth. IA administration of TNF-alpha resulted in statistically significant diminution of tumor size as compared to untreated controls and animals receiving IA 2% normal rat serum (NRS; P<0.05 at days 6, 8 and 10), regardless of the dose employed. The maximum growth inhibition with IA TNF-alpha was a 91% reduction in tumor volume that was achieved with a dose of 1 x 10(6) U TNF-alpha. These results demonstrate improved anti-tumor activity with the IA administration of TNF-alpha over the IV route in a regionally confined mammary adenocarcinoma. IA administration of biologic response modifiers like TNF-alpha may therefore be a useful approach for the hepatic chemoembolization of breast adenocarcinomas metastatic to the liver.

Patient Poets: Illness from Inside Out invites readers to consider what caregivers and medical professionals may learn from poetry by patients. It offers reflections on poetry as a particularly apt vehicle for articulating the often isolating experiences of pain, fatigue, changed life rhythms, altered self-understanding, embarrassment, resistance, and acceptance.