Mark R. Pittelkow

TGF-β1 inhibition of c-myc transcription and growth in keratinocytes is abrogated by viral transforming proteins with pRB binding domains

TGF-beta 1 is demonstrated to inhibit skin keratinocyte proliferation when added during the G1 phase of the cell cycle. Human foreskin keratinocytes transformed with either HPV-16 or -18 or SV40, however, were resistant to the growth inhibitory effects of TGF-beta 1. Since TGF-beta 1 appears to inhibit keratinocyte growth through down-regulation of c-myc, it was hypothesized that these DNA tumor viruses might be modulating the response to TGF-beta 1 via this pathway. Transient expression of proteins HPV-16 E7, adenovirus type 5 E1A, and SV40 large T antigen is demonstrated to block TGF-beta 1 suppression of c-myc transcription. This effect was not observed with DNA tumor virus transforming proteins mutated in their pRB binding domain. These observations indicate that pRB or another protein that interacts with this binding domain mediates TGF-beta 1 regulation of c-myc gene expression and growth inhibition.

Malignant Melanoma in the 21st Century, Part 1: Epidemiology, Risk Factors, Screening, Prevention, and Diagnosis

Malignant melanoma is an aggressive, therapy-resistant malignancy of melanocytes. The incidence of melanoma has been steadily increasing worldwide, resulting in an increasing public health problem. Exposure to solar UV radiation, fair skin, dysplastic nevi syndrome, and a family history of melanoma are major risk factors for melanoma development. The interactions between genetic and environmental risk factors that promote melanomagenesis are currently the subject of ongoing research. Avoidance of UV radiation and surveillance of high-risk patients have the potential to reduce the population burden of melanoma. Biopsies of the primary tumor and sampling of draining lymph nodes are required for optimal diagnosis and staging. Several clinically relevant pathologic subtypes have been identified and need to be recognized. Therapy for early disease is predominantly surgical, with a minor benefit noted with the use of adjuvant therapy. Management of systemic melanoma is a challenge because of a paucity of active treatment modalities. In the first part of this 2-part review, we discuss epidemiology, risk factors, screening, prevention, and diagnosis of malignant melanoma. Part 2 (which will appear in the April 2007 issue) will review melanoma staging, prognosis, and treatment.

New Techniques for the In Vitro Culture of Human Skin Keratinocytes and Perspectives on Their Use for Grafting of Patients With Extensive Burns

Human keratinocytes can be cultured in vitro and used for autografting of the injured epidermis. In this article, we describe our culture methods for propagating autologous keratinocytes for grafting, and we present an overview of the questions raised by the use of such methods. Our culture method involves a two-phase technique. Phase 1 is performed in serum-free medium and yields large quantities of a homogeneous, highly proliferative, basal cell-like population. Phase 2 involves the induced formation of cohesive, stratified sheets of differentiated keratinocytes resembling normal epidermis that can be used for grafting. This two-phase technique was used for preparation of autografts for full-thickness wounds of a massively burned patient. Important questions about the functional potential of cultured keratinocytes and the long-term behavior of cultured epidermal autografts in vivo remain to be answered.

Possible role of transforming growth factor α in the pathogenesis of Ménétrier's disease: Supportive evidence from humans and transgenic mice

Ménétriers disease is an uncommon disorder of unknown etiology characterized by enlarged gastric folds with foveolar hyperplasia and cystic dilatation of gastric glands. Biochemical features that are seen frequently include hypoproteinemia, hypochlorhydria, and increased gastric mucus. Because transforming growth factor alpha (TGF alpha) is an epithelial cell mitogen that inhibits gastric acid secretion and increases gastric mucin content, we hypothesized that its altered expression might be involved in the pathogenesis of this disease. Therefore, we characterized TGF alpha immunoreactivity in the gastric mucosa of 4 patients with Ménétriers disease. In contrast to the normal pattern of TGF alpha immunostaining in which TGF alpha appears most concentrated in parietal cells, there was intense staining in the majority of mucous cells in the gastric mucosa of patients with Ménétriers disease. In one patient from whom sufficient fresh tissue was obtained to isolate RNA, expression of TGF alpha and the epidermal growth factor receptor was higher in the gastric mucosa relative to a normal control. In addition, metallothionein-TGF alpha transgenic mice, which overexpress TGF alpha in gastric mucosa, show a number of features characteristic of Ménétriers disease. These include foveolar hyperplasia and glandular cystic dilatation, increased gastric neutral mucin staining, and reduced basal and histamine-stimulated rates of acid production. Taken together, observations derived from the human material and correlation with data from a transgenic mouse model support an important role for TGF alpha in the pathogenesis of Ménétriers disease.

WHIM syndrome, an autosomal dominant disorder: Clinical, hematological, and molecular studies

The acronym WHIM refers to Warts, Hypogammaglobulinemia, Infections, and Myelokathexis. The latter refers to the retention of white cells in the marrow, which becomes hypercellular. We have found approximately 20 examples of WHIM syndrome in the literature under various designations; the first examples are Zuelzer [1964] and Krill et al. [1964]. Chronic noncyclic neutropenia and hypercellular bone marrow represent defective release of marrow cells into the peripheral stream (myelokathexis). The hypermature neutrophils are bizarre in form. Condensed nuclei connected by long, stringy filaments and vacuolated cytoplasm suggest apoptosis. Fever or other stress increases the release of neutrophils. Hypogammaglobulinemia is marked and associated with recurrent upper respiratory infections (sinusitis, tonsillitis, otitis media, pneumonia). Patients have numerous warts, some venereal, with resultant cervical and vulval premalignant dysplasia. We report on a kindred of 6 affected individuals in 3 generations with autosomal dominant WHIM syndrome. The sex ratio among reported patients and in our kindred is 17 female to 8 male. Because there had been no male-to-male transmssion, search of the entire X-chromosome including the pseudoautosomal area was carried out and no linkage was found. Recently, the propositus has had an unaffected daughter, confirming our finding that the gene is not X-linked. A genome-wide search is being carried out.

Antiphospholipid syndrome and the skin.

The antiphospholipid syndrome is an acquired multisystem disorder of hypercoagulation, which may be primary or secondary to underlying diseases. Serologic markers for the syndrome are the lupus anticoagulant and anticardiolipin antibodies. Clinical features include recurrent thrombotic events (arterial or venous), repeated fetal loss, and thrombocytopenia. Cutaneous manifestations may occur as the first sign of antiphospholipid syndrome. These include livedo reticularis, necrotizing vasculitis, livedoid vasculitis, thrombophlebitis, cutaneous ulceration and necrosis, erythematous macules, purpura, ecchymoses, painful skin nodules, and subungual splinter hemorrhages. Antiphospholipid syndrome may also be associated rarely with anetoderma, discoid lupus erythematosus, cutaneous T-cell lymphoma, or disorders that closely resemble Sneddon or Degos syndromes. Noninflammatory vascular thrombosis is the most frequent histopathologic feature observed. Prophylaxis and treatment of thrombosis in patients with antiphospholipid syndrome relies principally on anticoagulant and antiplatelet agents.

Monoclonal gammopathies and associated skin disorders

The monoclonal gammopathies are characterized by clonal proliferation of plasma cells and other clonally related cells in the B-cell lineage. These disorders include monoclonal gammopathy of undetermined significance, multiple myeloma, Waldenström macroglobulinemia, heavy chain diseases, plasmacytoma, and primary amyloidosis. Many skin disorders have been described in association with monoclonal gammopathies. This article provides an introduction to the definition, detection, natural course, and spectrum of monoclonal gammopathies and a brief discussion of pathogenesis. The article also reviews the skin disorders associated with monoclonal gammopathies, categorizes the association, and evaluates the strength of the association.

Defective tetrahydrobiopterin and catecholamine biosynthesis in the depigmentation disorder vitiligo

Patients with the depigmentation disorder vitiligo lack the capacity to synthesize the melanins from L-tyrosine via the essential activity of tyrosinase. The aim of this study has been to examine both the supply of the substrate (L-tyrosine) and the regulation of tyrosinase in the epidermis of subjects with vitiligo. Patients with this depigmentation disorder have a 3- to 5-fold increase in GTP-cyclohydrolase I activity leading to an excessive de novo synthesis of (6R)5,6,7,8 tetrahydrobiopterin (6-BH4). Continuous production of 6-BH-4 leads to: (1) an accumulation of the non-enzymatic byproduct 7-tetrahydropterin (7-BH4) in the epidermis, and (2) increased synthesis of the catecholamines in keratinocytes, leading to an excess of norepinephrine in both the plasma and urine of these patients. In vitiligo, the time-dependent production of 7-BH4 is caused by decreased 4a-hydroxytetrahydrobiopterin dehydratase activity; the essential enzyme for recycling and maintaining normal levels of 6-BH-4. In the epidermis and in cultured melanocytes, 7-BH4 is a potent competitive inhibitor of phenylalanine hydroxylase (Ki = 10(-6) M) and its accumulation in the epidermis of patients with vitiligo blocks the supply of L-tyrosine from L-phenylalanine. 4a-hydroxytetrahydrobiopterin dehydratase has a dual function as the activator/dimerization catalyst for the transcription factor hepatocyte nuclear factor I (HNF-I). HNF-I binds to a 16-base inverted palindrome which seems to be present on the promoters of both the tyrosinase and phenylethanolamine-N-methyl transferase (PNMT) genes. Therefore, defective 4a-hydroxytetrahydrobiopterin dehydratase in vitiligo influences not only the supply of L-tyrosine but also the transcription of the tyrosinase gene in melanocytes. Furthermore, a similar transcriptional regulation of the PNMT gene in keratinocytes offers a possible explanation for the accumulation of norepinephrine in these patients.

Cutaneous manifestations of cryoglobulinemia: Clinical and histopathologic study of seventy-two patients

In the 72 cases of cryoglobulinemia reviewed, erythematous to purpuric macules or papules were present in 92%. Infarction, hemorrhagic crusts, and ulcers were present in 10% to 25% of the patients and were relatively more common in type I cryoglobulinemia than in the other types. Postinflammatory hyperpigmentation was noted in 40%. Lesions on the leg were common in all types of cryoglobulinemia; however, lesions on the head and mucosal surfaces suggested type I cryoglobulinemia. Histopathologic features were classified as vasculitis in 50%, inflammatory or noninflammatory purpura in 15%, noninflammatory hyaline thrombosis in 10%, and postinflammatory sequelae in 10%. Noninflammatory hyaline thrombosis was relatively more frequent in type I. Thus erythematous to purpuric lesions on the legs and leukocytoclastic vasculitis are the common cutaneous findings in cryoglobulinemia. Type I cryoglobulinemia is suggested by noninflammatory hyaline thrombosis, cutaneous infarction, hemorrhagic crusts, skin ulcerations, and lesions of the head and neck and of oral or nasal mucosa.

The clinicopathologic spectrum of lymphomatoid papulosis: study of 31 cases.

Herein we review the Mayo Clinic experience with thirty-one cases of lymphomatoid papulosis seen since 1965. All patients had chronic, recurrent, and self-healing erythematous papulonodular lesions, which often became pustular, ulcerated, and resolved with scarring. The clinical features often corresponded to those seen in Mucha-Habermann disease; however, the predominant histopathologic feature was an infiltrate composed primarily of atypical lymphoid cells suggestive of malignant lymphoma. In six patients, a lymphoproliferative disorder was eventually diagnosed. There were two cases of mycosis fungoides (stage I), one case of nodular sclerosing Hodgkins disease, and three cases of malignant lymphoma--one diffuse mixed large and small cell type with features of T-immunoblastic type, one diffuse large cell type, and one follicular small cleaved cell type. The clinical course of the lymphomatoid papulosis was unaffected by chemotherapy for the lymphoproliferative disorder. Our data indicate that, with sufficient duration of follow-up, malignant lymphoma may develop in some patients with lymphomatoid papulosis.