Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06126 (CD1a)
 2,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Atypical fibroxanthoma (AFX) is a rare skin tumor that generally pursues an indolent course despite its alarming histological appearances. It is important for the pathologist to distinguish this neoplasm from more aggressive lesions that may show very similar histological features. Recently, it has been suggested that demonstration of CD117 is of value in identifying AFX. To test this hypothesis, 50 cases of AFX were stained immunohistochemically for CD117 to determine the diagnostic value of this antibody. Cases were also stained for tryptase to identify mast cells, which are CD117 positive. In addition, S100 and CD1a stains were performed to assess any possible contribution of melanocytes or Langerhans cells to CD117 staining. Only 1 of 50 AFXs (2%) showed CD117 positivity in the neoplastic cells, but all tumors demonstrated included CD117- and tryptase-positive mast cells in similar distribution. CD117 is only rarely stainable in the neoplastic cells of AFX and is therefore not useful in identifying these tumors. Mast cells are also CD117 positive, frequently present in AFX, and can lead to misinterpretation. Using immunohistochemistry for mast cell tryptase may be of value where there is doubt as to the nature of CD117-positive cells in neoplasms.
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PMID:CD117 is not a useful marker for diagnosing atypical fibroxanthoma. 2052 72

Langerhans cell sarcoma is a very rare and aggressive tumor of Langerhans cell lineage, for which aberrant expression of T-cell-related antigens has not yet been reported in a primary skin tumor. The authors describe the first known case of a primary cutaneous Langerhans cell sarcoma with lineage infidelity and use comparative genomic hybridization to investigate the genetic composition of the tumor and detect DNA copy number alterations throughout its entire genome. The case involves a 62-year-old woman who presented with an irregular nodule on the forehead surrounded by smaller lesions in its vicinity. The clinical impression was melanoma with satellitosis. The biopsy specimen showed an epidermotropic tumor with moderate-to-marked cellular pleomorphism and significantly increased mitotic rate but no necrosis. The immunoprofile of the lesion was remarkable, as next to common Langerhans cell markers: Langerin, CD1a, S100, and CD4; it also exhibited an aberrant T-cell phenotype with the expression of CD2, CD3, and CD43. In addition, fascin and CD30 were also expressed, further exaggerating potential diagnostic pitfalls. Langerhans cell lineage was confirmed by the demonstration of characteristic Birbeck granules on electron microscopy. Whole genome analysis for copy number changes and loss of heterozygosity showed a complex karyotype with variable hyperdiploidy and numerous allelic imbalances. Significant findings included a homozygous deletion at 9p21 involving the CDKN2A and loss of heterozygosity at 17p involving TP53 gene, coupled with a TP53 missense mutation. Despite reexcision and multiagent systemic chemotherapy, the patient died of metastasis 2 years after diagnosis. This case is an outstanding example of lineage infidelity in a hematologic malignancy and the utilization of comparative genomic hybridization in characterizing its genetic abnormalities.
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PMID:Langerhans cell sarcoma with lineage infidelity/plasticity: a diagnostic challenge and insight into the pathobiology of the disease. 2636 46