Pleiotrophin expression correlates with melanocytic tumor progression and metastatic potential.

BACKGROUND: Gene expression profiling of melanoma and nevic tissue has demonstrated that pleiotrophin (PTN) is significantly overexpressed in human melanomas. METHODS: To further evaluate PTN expression in melanocytic lesions, protein immunohistochemistry was performed on the spectrum of melanocytic lesions. RESULTS: Melanocytic nevi were consistently negative (n=58). In contrast, the great majority of metastatic melanomas were positive (33/34, 97%). The analysis of 34 primary melanomas demonstrated PTN positivity in 20 lesions while 14 lesions were negative. Within the primary melanomas, PTN immunoreactivity was associated with metastasis (p=0.0004) and decreased melanoma-related survival (p=0.0444). Univariate analysis of PTN immunoreactivity predicted an increased risk for metastasis (relative risk 9.1, p=0.003). CONCLUSIONS: The results of this study confirm previous gene profiling data showing differential PTN expression between melanocytic nevi and melanomas. In addition, lesional PTN expression is associated with metastatic potential and may be a prognostic factor for melanomas.

Aggressive digital papillary adenocarcinoma: a case report and review of the literature.

We report a case of an aggressive digital papillary adenocarcinoma (ADPA) on the right thumb of a 48-year-old white man. Histologic evaluation of the initial biopsy demonstrated features consistent with those proposed for aggressive digital papillary adenoma; however, re-excision of the remaining lesion revealed histologic features consistent with aggressive digital papillary adenocarcinoma. These tumors have a high rate of local recurrence and can metastasize, occasionally resulting in mortality. Our case demonstrates that even if the histologic criteria of aggressive digital papillary adenocarcinoma are met, the lesion may still represent an aggressive digital papillary adenocarcinoma (ADPAca). In agreement with a recent study by Duke et al., this case supports the idea that aggressive digital papillary lesions should be classified as aggressive digital papillary adenocarcinoma.

Scleromyxedema: successful treatment of cutaneous and neurologic symptoms.

Scleromyxedema is a rare systemic disorder characterized by cutaneous sclerosis and papulosis, accompanied by deposition of mucin in the skin and other organs. We describe a case of scleromyxedema in a 62-year-old man. The cutaneous symptoms of the disorder were preceded by episodes of acute central nervous system dysfunction that included mental confusion, hemiparesis, tremor, and migraine. As the cutaneous symptoms progressed, the patient experienced persistent confusion and difficulty concentrating. Therapy with melphalan and plasmapheresis led to complete resolution of the cutaneous symptoms as well as near-resolution of the neurologic symptoms. This is the first report to describe the successful treatment of the cutaneous symptoms of scleromyxedema accompanied by reversal of chronic neurologic dysfunction.

Ultraviolet B-induced squamous epithelial and melanocytic cell changes in a xenograft model of cancer development in human skin.

We previously demonstrated that precancers (actinic keratoses and dysplasias) and squamous cell carcinomas (SCCs) develop in one quarter of human neonatal foreskins grafted onto recombinase-activating gene-1-knockout mice treated once with 7,12-dimethylbenz[a]anthracene (DMBA) followed by chronic intermediate-range ultraviolet (UV) B light irradiation. The goals of this study were to determine if a longer UVB exposure followed by further observation would increase the number of precancers and invasive cancers and to evaluate whether this model results in changes in p53 expression and cell proliferation similar to those seen in sun-damaged normal skin, actinic keratoses, and SCCs. The treatment consisted of a single dose of DMBA followed by 500 J/m2 UVB radiation administered three times weekly for at least 5 mo. Histologic changes (cysts, hyperplasias, precancers, and/or invasive cancers) were seen in 24 of 25 treated xenografts but not in controls. Ten of 25 grafts (40%) had two or more histological changes, and two human SCCs developed. After seven or more months of UV exposure and a total time from DMBA treatment to killing of 12-18 mo, 83% (15 of 18) of specimens developed squamous precancer or SCC of human origin, and 44% (eight of 18) developed melanocytic hyperplasia or melanoma. The change from moderate dysplasias to SCC required longer UV exposure (median, 11 mo), and 5 mo more observation than did the development of mild dysplasias (median UV exposure, 7 mo; median DMBA to death time, 12 mo). There was a direct correlation between both p53 expression and cell proliferation and the degree of histologic alteration both in squamous epithelial and melanocytic cells.

UVB induces atypical melanocytic lesions and melanoma in human skin.

A direct causal relationship between ultraviolet (UV) light in the B range and melanoma development has not been demonstrated in humans; this study aims to establish causality. A total of 158 RAG-1 mice, grafted with human newborn foreskin, were separated into four groups and observed for a median of 10 months: 1) no treatment, 2) a single treatment with 7,12-dimethyl(a)benzanthracene (DMBA), 3) UVB irradiation at 500 J/m2 alone, three times weekly, and 4) a combination of DMBA and UVB. Twenty-three percent of 40 normal human skin grafts treated with UVB only and 38% of 48 grafts treated with the combination of DMBA and UVB developed solar lentigines within 5 to 10 months of treatment. Melanocytic hyperplasia was found in 73% of all UVB-treated xenografts. Histological melanocytic changes resembling lentigo and lentigo maligna were seen in several skin grafts treated with both DMBA and UVB. In one graft of an animal treated with a combination of DMBA and UVB, a human malignant melanoma, nodular type, developed. This experimental system demonstrates that chronic UVB irradiation with or without an initiating carcinogen can induce human melanocytic lesions, including melanoma.

Molecular determinants of the myristoyl-electrostatic switch of MARCKS.

MARCKS is a protein kinase C (PKC) substrate which binds calcium/calmodulin and actin, and which has been implicated in cell motility, phagocytosis, membrane traffic, and mitogenesis. MARCKS cycles on and off the membrane via a myristoyl electrostatic switch (McLaughlin, S., and Aderem, A.(1995) Trends Biochem. Sci. 20, 272-276). Here we define the molecular determinants of the myristoyl-electrostatic switch. Mutation of the N-terminal glycine results in a nonmyristoylated form of MARCKS which does not bind membranes and is poorly phosphorylated. This indicates that myristic acid targets MARCKS to the membrane, where it is efficiently phosphorylated by PKC. A chimeric protein in which the N terminus of MARCKS is replaced by a sequence, which is doubly palmitoylated, is phosphorylated by PKC but not released from the membrane. Thus two palmitic acid moieties confer sufficient membrane binding energy to render the second, electrostatic membrane binding site superfluous. Mutation of the PKC phosphorylation sites results in a mutant which does not translocate from the membrane to the cytosol. A mutant in which the intervening sequence between the myristoyl moiety and the basic effector domain is deleted, is not displaced from the membrane by PKC dependent phosphorylation, fulfilling a theoretical prediction of the model. In addition to the nonspecific membrane binding interactions conferred by the myristoyl-electrostatic switch, indirect immunofluorescence microscopy demonstrates that specific protein-protein interactions also specify the intracellular localization of MARCKS.

Cytologic manifestations of respiratory syncytial virus pneumonia in bronchoalveolar lavage fluid: a case report.

BACKGROUND: Respiratory syncytial virus (RSV) pneumonia in immunocompromised patients, especially bone marrow transplant recipients, is associated with high mortality. Early diagnosis in these cases is important because antiviral therapy with ribavirin is effective in reducing mortality. CASE: A 45-year-old male with multiple myeloma who underwent autologous peripheral stem cell transplantation subsequently developed bilateral pulmonary infiltrates. A bronchoalveolar lavage specimen demonstrated the cytologic changes associated with RSV pneumonia. Infection with RSV was confirmed by indirect immunofluorescence, enzyme immunoassay and, later, on histology and electron microscopy at autopsy. CONCLUSION: Recognition of the cytologic changes associated with RSV pneumonia in immunodeficient patients can be life saving since this would initiate confirmatory immunologic studies and therapy.

Cloning and molecular characterization of the murine macrophage "68-kDa" protein kinase C substrate and its regulation by bacterial lipopolysaccharide.

We have isolated and characterized a cDNA clone encoding the murine macrophage 68-kDa protein kinase C substrate, which is homologous to the 80- to 87-kDa protein identified by the acronym MARCKS (myristoylated alanine-rich C kinase substrate). The murine MARCKS cDNA clone encodes an acidic protein of 309 amino acids with a calculated molecular weight of 29,661. Transfection of the murine MARCKS gene into TK-L fibroblasts produced a myristoylated protein kinase C substrate that migrated on SDS/PAGE with an apparent molecular mass of 68 kDa. Peptide mapping studies indicated that MARCKS produced by the transfected gene was indistinguishable from the endogenous murine macrophage protein. Comparison of the murine macrophage sequence with the previously published chicken and bovine brain sequences revealed two conserved domains: an N-terminal membrane-binding domain and a phosphorylation domain that also contains calmodulin and actin binding sites. In murine peritoneal macrophages, bacterial lipopolysaccharide increased MARCKS mRNA levels by greater than 30-fold. Multiple MARCKS transcripts were observed and could be accounted for by differential polyadenylylation and incomplete processing. Genomic Southern blot analysis suggested a single MARCKS gene per haploid genome.