Purpose The pathogenesis of CTCL remains only partially understood. A number of recent studies attempted to identify novel diagnostic markers and future therapeutic targets. One group of antigens, cancer-testis (CT) antigens, normally present solely in testicular germ cells, can be ectopically expressed in a variety of cancers. Currently only a few studies attempted to investigate the expression of CT antigens in CTCL. Experimental Design In the present work we test the expression of CT genes in a cohort of CTCL patients, normal skin samples, skin from benign inflammatory dermatoses and in patient-derived CTCL cells. We correlate such expression with the p53 status and explore molecular mechanisms behind their ectopic expression in these cells. Results Our findings demonstrate that SYCP1, SYCP3, REC8, SPO11 and GTSF1 genes are heterogeneously expressed in CTCL patients and patient-derived cell lines, while cTAGE1 was found to be robustly expressed in both. Mutated p53 status did not appear to be a requirement for the ectopic expression of CT antigens. While T cell stimulation resulted in a significant upregulation of STAT3 and JUNB expression, it did not significantly alter the expression of CT antigens. Treatment of CTCL cells in-vitro with Vorinostat or Romidepsin Histone Deacetylase inhibitors resulted in a significant dose-dependent upregulation of mRNA, but not protein. Further expression analysis demonstrated that SYCP1, cTAGE1 and GTSF1 were expressed in CTCL, but not in normal skin or benign inflammatory dermatoses. Conclusions A number of CT genes are ectopically expressed in CTCL patients and can be used as biomarkers or novel targets for immunotherapy.

Deregulation of STAT signaling has been implicated in the pathogenesis for a variety of cancers, including CTCL. Recent reports indicate that loss of STAT4 expression is an important prognostic marker for CTCL progression and is associated with the acquisition of T helper 2 cell phenotype by malignant cells. However, little is known about the molecular mechanism behind the downregulation of STAT4 in this cancer. In the current work we test the expression of STAT4 and STAT6 via RT-PCR and/or Western Blot in CTCL lesional skin samples and in immortalized patient-derived cell lines. In these malignant cell lines we correlate the expression of STAT4 and STAT6 with the T helper (Th) phenotype markers and test the effect of Histone Deacetylase (HDAC) inhibitors and siRNA-mediated knock down of miR-155 on STAT4 expression. Our findings demonstrate that STAT4 expression correlates with Th1 phenotype, while STAT6 is associated with the Th2 phenotype. Our results further document that STAT4 and STAT6 genes are inversely regulated in CTCL. Treatment with HDAC inhibitors upregulates STAT4 expression, while at the same time decreases STAT6 expression in MyLa cells. Also, siRNA-mediated knock down of miR-155 leads to upregulation in STAT4 expression in MyLa cells. In summary, our results suggest that loss of STAT4 expression and associated switch to Th2 phenotype during Mycosis Fungoides progression may be driven via aberrant histone acetylation and/or upregulation of oncogenic miR-155 microRNA.

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Allergic contact dermatitis (ACD) most commonly presents as an eczematous reaction; however, a variety of non-eczematous eruptions have also been reported, including erythema multiforme (EM)-like lesions. 1-3 The pathogenesis of true EM is known to be type III hypersensitivity immune complex-mediated, affecting small vessels in the skin and mucosa. 4 The pathogenesis of EM-like lesions which appear secondary to ACD, however, remains elusive but is hypothesized to be a result of a type IV reaction mediated by T cells, as is the case in eczematous contact dermatitis. 2,5 We herein present a case of ACD in a pediatric patient who subsequently developed an EM-like reaction and discuss this potentially underreported complication to plant-induced contact dermatitis.

Allergic reactions to polymyxin B are not rare, and this antibiotic warrants inclusion in the standard patch testing series.