ABCB5-Targeted Chemoresistance Reversal Inhibits Merkel Cell Carcinoma Growth.

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer with profound but poorly understood resistance to chemotherapy, which poses a significant barrier to clinical MCC treatment. Here we show that ATP-binding cassette member B5 (ABCB5) confers resistance to standard-of-care MCC chemotherapeutic agents and provide proof-of-principle that ABCB5 blockade can inhibit human MCC tumor growth through sensitization to drug-induced cell cytotoxicity. ABCB5 expression was detected in both established MCC lines and clinical MCC specimens at levels significantly higher than those in normal skin.

Merkel cell carcinoma expresses vasculogenic mimicry: demonstration in patients and experimental manipulation in xenografts.

Merkel cell carcinoma (MCC) is a highly virulent cutaneous neoplasm that, like melanoma, is a frequent cause of patient morbidity and mortality. The cellular mechanisms responsible for the aggressive behavior of MCC remain unknown. Vasculogenic mimicry (VM) is a phenomenon associated with cancer virulence, including in melanoma, whereby anastomosing laminin networks form in association with tumor cells that express certain endothelial genes.

Palliative treatment for in-transit cutaneous metastases of Merkel cell carcinoma using surface-mold computer-optimized high-dose-rate brachytherapy.

Purpose: The objective of this study was to evaluate the palliative treatment benefit of surface-mold computer-optimized high-dose-rate brachytherapy (SMBT) for in-transit cutaneous metastases of Merkel cell carcinoma (MCC).

Methods: Ten patients with in-transit cutaneous MCC metastases were treated with SMBT at the Dana-Farber/Brigham & Women's Cancer Center between 2006 and 2012.

Results: The median age at diagnosis was 76 years (range, 63-87 years).

Low-dose high-dose-rate brachytherapy in the treatment of facial lesions of cutaneous T-cell lymphoma.

Background: The use of many of the standard skin-directed mycosis fungoides (MF) therapies on facial skin may be limited by site-specific increased risks of side effects, excessive inflammation, and ocular toxicity.

Objective: Our study aimed to describe the levels of erythema, scale, and induration of facial lesions in MF before and after low-dose high-dose-rate surface applicator brachytherapy and to examine the overall clinical response to brachytherapy.

Methods: A total of 23 facial MF lesions in 10 patients were treated with high-dose-rate brachytherapy doses of 4 Gy per session for a total of 2 fractions at our multidisciplinary cutaneous oncology clinic between August 17, 2009, and March 12, 2012.

Tumor-specific T cells in human Merkel cell carcinomas: a possible role for Tregs and T-cell exhaustion in reducing T-cell responses.

Merkel cell carcinomas (MCCs) are rare but highly malignant skin cancers associated with a recently described polyomavirus. MCC tumors were infiltrated by T cells, including effector, central memory, and regulatory T cells. Infiltrating T cells showed markedly reduced activation as evidenced by reduced expression of CD69 and CD25.

Positron emission tomography/computed tomography imaging in Merkel cell carcinoma: a study of 270 scans in 97 patients at the Dana-Farber/Brigham and Women's Cancer Center.

Background: Merkel cell carcinoma (MCC) is a rare and lethal cutaneous neuroendocrine carcinoma. Imaging is crucial for accurate staging, which remains a strong predictor of survival, as well as earlier detection of recurrence and progression, which are common despite aggressive management. There is no consensus on the role of initial and subsequent imaging for MCC.

Improved detection suggests all Merkel cell carcinomas harbor Merkel polyomavirus.

A human polyomavirus was recently discovered in Merkel cell carcinoma (MCC) specimens. The Merkel cell polyomavirus (MCPyV) genome undergoes clonal integration into the host cell chromosomes of MCC tumors and expresses small T antigen and truncated large T antigen. Previous studies have consistently reported that MCPyV can be detected in approximately 80% of all MCC tumors.

Skin effector memory T cells do not recirculate and provide immune protection in alemtuzumab-treated CTCL patients.

Cutaneous T cell lymphoma (CTCL) is a cancer of skin-homing T cells with variants that include leukemic CTCL (L-CTCL), a malignancy of central memory T cells (T(CM)), and mycosis fungoides (MF), a malignancy of skin resident effector memory T cells (T(EM)). We report that low-dose alemtuzumab (αCD52) effectively treated patients with refractory L-CTCL but not MF. Alemtuzumab depleted all T cells in blood and depleted both benign and malignant T(CM) from skin, but a diverse population of skin resident T(EM) remained in skin after therapy.