Abstract |
Cutaneous T-cell lymphoma (CTCL) comprises distinct and often progressive stages of skin involvement by patches, plaques, and tumors. We have previously demonstrated that CTCL-derived malignant T-cell lines display loss of a tumor suppressor SHP-1 tyrosine phosphatase because of epigenetic silencing of its gene. The silencing is induced by an activated phosphorylated (p)-STAT3 transcription factor in cooperation with DNA methyltransferase 1 (DNMT1), the key member of the epigenetic gene silencing machinery. To determine at which stage of CTCL the loss of SHP-1 occurs and how it correlates with the expression of (p)-STAT3 and DNMT1, we examined by immunohistochemistry 47 formalin-fixed skin biopsies from various stages of CTCL. Six pairs of the biopsies were obtained before and after CTCL progression at the patch or plaque and tumor stage, respectively. In 5 of these pairs, we identified loss of SHP-1 expression in atypical lymphocytes at the tumor stage; less prominent SHP-1 loss was noted in 3 biopsies from the earlier stage. The SHP-1 loss was also observed in 5 of 6 tumor, 12 of 18 plaque, and only 2 of 11 patch stages in patients with single biopsies. The expression of (p)-STAT3 and DNMT1 could be identified in almost all cases in at least a subset of the lesional cells. Based on these findings, we postulate that expression of (p)-STAT3 and DNMT1 occurs at the early stages of CTCL, and that this expression alone seems insufficient to induce loss of SHP-1 expression. In turn, SHP-1 loss correlates with, and may contribute to, progression of CTCL.
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Authors | Agnieszka Witkiewicz, Puthiyaveettil Raghunath, Agnieszka Wasik, Jacqueline M Junkins-Hopkins, Dan Jones, Qian Zhang, Niels Odum, Mariusz A Wasik |
Journal | Human pathology
(Hum Pathol)
Vol. 38
Issue 3
Pg. 462-7
(Mar 2007)
ISSN: 0046-8177 [Print] United States |
PMID | 17239936
(Publication Type: Journal Article, Multicenter Study, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- STAT3 Transcription Factor
- STAT3 protein, human
- DNA (Cytosine-5-)-Methyltransferase 1
- DNA (Cytosine-5-)-Methyltransferases
- DNMT1 protein, human
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Topics |
- DNA (Cytosine-5-)-Methyltransferase 1
- DNA (Cytosine-5-)-Methyltransferases
(biosynthesis)
- Gene Silencing
- Humans
- Immunohistochemistry
- Lymphoma, T-Cell, Cutaneous
(pathology, physiopathology)
- Mycosis Fungoides
(pathology, physiopathology)
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
(biosynthesis)
- STAT3 Transcription Factor
(biosynthesis)
- Skin Neoplasms
(pathology, physiopathology)
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