A major limitation of exogenous vitamin D3 administration for the treatment of prostate cancer is the marginal, if any, clinical efficacy. We dissected the basis for the resistance to the vitamin D3 antitumor properties and specifically examined the effect of its major catabolic enzyme, CYP24A1, in prostate cancer. Local CYP24A1 expression levels and the effect of selective modulation were analyzed using tissue microarrays from needle core biopsy specimens and xenograft-bearing mouse models. CYP24A1 mRNA was elevated in malignant human prostate tissues compared to benign lesions. High CYP24A1 protein levels were seen in poorly differentiated and highly advanced stages of prostate cancer and correlated with parallel increase in the tumor proliferation rate. The use of CYP24A1 RNAi enhanced the cytostatic effects of vitamin D3 in human prostate cancer cells. Remarkably, subcutaneous and orthotopic xenografts of prostate cancer cells harboring CYP24A1 shRNA resulted in a drastic reduction in tumor volume when mice were subjected to vitamin D3 supplementation. CYP24A1 may be a predictive marker of vitamin D3 clinical efficacy in patients with advanced prostate cancer. For those with up-regulated CYP24A1, combination therapy with RNAi targeting CYP24A1 could be considered to improve clinical responsiveness to vitamin D3.
Background
Systemic forms of EBV‐associated T‐cell lymphoproliferative disorders of childhood (S‐EBV‐T‐LPD) comprise three major forms: EBV‐positive hemophagocytic lymphohistiocytosis (EBV‐HLH), systemic EBV‐positive T‐cell lymphoma (S‐EBV‐TCL), and systemic chronic active EBV infection (S‐CAEBV). These disorders occur rarely in children in Western countries. Here, we described eight children of such entities.
Design
Eight cases (six clinical and two autopsy) with S‐EBV‐T‐LPD of childhood were retrospectively identified from 1990 to 2015. Clinicopathologic parameters including histomorphology, immunophenotype, EBV studies, and T‐cell receptor gene rearrangement studies were recorded.
Results
Patients include five females and three males of Hispanic, Asian, and Caucasian origins with an age range of 14 months to 9 years. Fever, hepatosplenomegaly, cytopenias, abnormal EBV serologies, and very high EBV viral loads were common findings. Histologic findings showed EBV+ T‐cell infiltrates with variable degrees of architectural distortion and cytologic atypia ranging from no to mild cytologic atypia to overt lymphoma and tissue hemophagocytosis. All showed aberrant CD4+ or CD8+ T cells with dim to absent CD5, CD7, and CD3, and bright CD2 and CD45 by flow cytometry or loss of CD5 by immunohistochemistry. TCR gene rearrangement studies showed monoclonal rearrangements in all clinical cases (6/6). Outcomes were poor with treatment consisting of chemotherapy per the HLH‐94 or HLH‐2004 protocols with or without bone marrow transplant.
Conclusion
In this large pediatric clinicopathologic study of S‐EBV‐T‐LPD of childhood in the United States, EBV‐HLH, S‐EBV‐TCL, and S‐CAEBV show many overlapping features. Diagnosis is challenging, and overall outcome is poor using current HLH‐directed therapies.
A 49-year-old woman presented with fever, weight loss, night sweats, hematochezia, and acid reflux symptoms. Two large, firm cecal lesions were seen at colonoscopy, but multiple biopsies were inconclusive. The patient underwent a right hemicolectomy for a clinical diagnosis of colon cancer. Noncaseating granulomatous inflammation with background lymphocytes, plasma cells, and histiocytes exhibiting emperipolesis were identified. With these histologic features and immunoreactivity for S-100 protein and CD68, a diagnosis of Rosai-Dorfman disease was rendered. Other areas had storiform fibrosis admixed with numerous immunoglobulin G4 (IgG4)–positive plasma cells. Although a few preliminary reports have noted an increased number of IgG4-positive plasma cells in Rosai-Dorfman disease, the relationship between these 2 conditions is unclear. To our knowledge, this is the first case report of a possible association of colonic Rosai-Dorfman disease with an increased number of IgG4-positive plasma cells. Reviews of colonic Rosai-Dorfman disease and IgG4-related sclerosis are presented to heighten awareness of this rare presentation.
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