Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Melanocytic nevus cells in the dermis adopt many morphological features of Schwann cells. These differentiation-related changes typically are not observed in melanomas. However, nevus cells do not fully recapitulate a Schwann cell phenotype, because they lack expression of mature myelin-associated proteins. In this study, melanocytic nevi and malignant melanomas were examined by immunohistochemistry for expression of low-affinity nerve growth factor receptor (p75NGFR), neural cell adhesion molecule (CD56/N-CAM), and growth-associated phosphoprotein-43 (GAP-43). These three proteins define the earliest stages of Schwann cell development but are not expressed in myelinated Schwann cells or normal melanocytes. p75NGFR was expressed in 25 of 25 (100%) and CD56/N-CAM and GAP-43 in 23 of 25 (92%) nevi, predominantly in type C nevus cells and nevic corpuscles. Most (84%) of the nevi expressed all three proteins. In primary invasive and metastatic melanoma, expression of each of the three proteins was limited to </=20% of lesions but was not observed in any melanoma in situ (chi(2 )P < 0.0001). None of the melanomas expressed all three proteins (ANOVA P < 0.0001). These data confirm and extend earlier studies by showing that terminal differentiation of melanocytes in the dermis recapitulates some aspects observed in the earliest stages of Schwann cell development and that invasive melanomas follow a divergent pathway. Studying these early differentiation events may help to identify specific defects in the relevant signaling pathways and establish tenable targets for therapy of advanced-stage melanoma.
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PMID:Divergent cellular differentiation pathways during the invasive stage of cutaneous malignant melanoma progression. 1043 47

Two of the most challenging areas in dermatopathology are lymphoproliferative disorders and melanocytic lesions. We present a case of peripheral T-cell lymphoma occurring with an intradermal melanocytic proliferation. A 63-year-old Caucasian man presented with a 12-cm edematous, erythematous to violaceous, scalp ulceration that had enlarged over six months. Previous biopsies showed reactive changes which were concerning for infection. The last biopsies showed small to intermediate sized, angulated cells with clear cytoplasm within the dermis, with extension into the epidermis. These cells stained positive with markers for CD3, CD45RO and CD43, yet showed decreased expression of pan-T-cell markers CD5 and CD7, and absent expression of CD4, CD8, CD56 and CD57 and EBV. Molecular studies showed a clonal T-cell receptor gamma chain gene rearrangement. The diagnosis was peripheral T-cell lymphoma, unspecified. Another biopsy from an indurated area separate from the ulcer showed scattered, enlarged cells embedded in the same lymphocytic infiltrate. No mitotic figures were identified. These cells stained for S100 and Melan-A, in a partly nested arrangement. This was felt to represent a melanocytic nevus. This case likely represents an extraordinary coincidence of two distinctly different neoplasms.
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PMID:Cutaneous T-cell lymphoma occurring with a melanocytic proliferation, masquerading as a nonhealing ulcer with reactive changes. 2000 51

Mortality from melanoma, the deadliest of skin cancers, continues to increase in all age groups. A small number of melanomas spontaneously regress. In vitro studies suggest a role for the natural killer cell in effecting regression. In this study, the goal was to determine if natural killer cells are preferentially involved in the cytotoxic response in regressing lesions. Forty-two cases were selected: nevi with regression, nonregressing melanoma with brisk inflammation, and regressing melanoma. Sections were stained with hematoxylin and eosin and immunostained for CD8, CD56, and T-cell intracytoplasmic antigen 1. Numbers of total lymphocytes, CD8-positive lymphocytes, and T-cell intracytoplasmic antigen 1-positive lymphocytes did not differ among the 3 populations or based on location. CD56 positivity was significantly different among the 3 populations. Regressing melanomas showed the greatest CD56 activity, followed by regressing nevi, whereas inflamed, nonregressing melanomas showed the least. CD56(+) lymphocytes were mostly counted in areas of early regression. The natural killer cell could plausibly play a role in the occurrence of regression as a cytotoxic effector cell or as a mediator of the cytotoxic mechanism.
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PMID:Association between natural killer cells and regression in melanocytic lesions. 2167 35