Klaus Hou-Jensen

Factor VIII related antigen as an endothelial cell marker in benign and malignant diseases

The presence and distribution of Factor VIII related antigen (FVIIIR:Ag) in formalin fixed, paraffin embedded tissue were studied in benign and malignant vascular tumors, inflammatory vascular diseases, normal tissue from various organs and a number of malignant tumors. The unlabeled peroxidase-anti-peroxidase method was utilized. Immunostaining was observed only in endothelial cells, in tumor cells of endothelial cell origin and in megakaryocytes and platelets. The staining method gave a distinct picture of the vascular pattern in all types of tissue examined. The demonstration of FVIIIR: Ag by means of the immunoperoxidase technique is considered a valuable method in diagnosing tumors of vascular origin. The method also facilitates detection of vascular invasion of malignant tumors in small caliber vessels.

Primary cutaneous B-cell lymphoma : a clinical, histological, phenotypic and genotypic study of 21 cases

The clinical, histological, phenotypic and genotypic features of 21 primary cutaneous B‐cell lymphomas (CBCLs) have been investigated. The patients were 13 men and eight women aged 34–91u2003years (median 67) at diagnosis. Eighteen patients had localized disease, and three had multiple skin lesions at diagnosis. Twelve patients developed cutaneous or extracutaneous recurrences, and five died from malignant lymphoma 7–84u2003months (median 36) after diagnosis. Histological examination showed features of marginal zone/mucosa‐associated lymphoid tissue (MALT)‐type lymphoma in 12 cases. Three of these had transformed to diffuse large B‐cell lymphoma (DLBCL) in relapse biopsies. The remaining cases were seven primary DLBCLs and two cases tentatively classified as follicle centre cell (FCC) lymphoma. The neoplastic B cells showed similar phenotypes and genotypes in most cases (CD20+, CD79+, CD5–, CD10–, cyclin D1–, bcl‐2+, bcl‐x–, bax–, t(14;18)‐negative). p53 protein was expressed in five cases, and four harboured mis‐sense or loss‐of‐function mutations in the p53 gene. Deletion or promoter region hypermethylation of the p16INK4a gene was detected in two patients with DLBCL. The level of retinoblastoma protein expression and the proliferative fraction were significantly higher in DLBCL (>u200350%) than in MALT‐ or FCC‐type lymphomas (<u200310%). Features associated with an unfavourable prognosis were the presence of multiple skin lesions at diagnosis, transformation from MALT‐type lymphoma to DLBCL, and possibly p16INK4a aberrations. It is concluded that most CBCLs are dissimilar from FCC lymphomas and seem to be more closely related to marginal zone/MALT‐type lymphomas. It is also suggested that there are fundamental differences between DLBCL and other histological categories of CBCL, indicating that cutaneous DLBCL is a separate entity with an increased growth potential and genetic features similar to DLBCL originating in other anatomical sites.

In situ immunological characterization of Langerhans cells with monoclonal antibodies: Comparison with other dendritic cells in skin and lymph nodes

The antigenic properties of epidermal Langerhans cells (LC) were determined and compared with those of non-lymphoid dendritic dermal cells (DDC), interdigitating reticulum cells (IRC), dendritic reticulum cells (DRC), and histiocytic reticulum cells (HRC) by examination of serial and double immunoenzymatic and -fluorescence stained frozen sections of skin and lymph node biopsies. All of these cell types expressed leucocyte common antigen. LC, DDC, and IRC demonstrated similar antigenic phenotypes (HLA-DR+, Leu3+, OKT6+/−, anti-C3 receptor−, R4/23−, Ig-complex−, M02−), whereas the antigenic properties on DRC (HLA-DR−, Leu3−, OKT6−, anti-C3 receptor+, R4/23+, Ig-complex+, M02−) and HRC (HLA-DR+/−, Leu3−, OKT6−, anti-C3 receptor+ R4/23−, Ig-complex+, MO2+) were markedly different. These data suggest that LC, DDC, and IRC are closely interrelated cell types, and support the concept that DRC and HRC are unique cell types which do not appear to be related to LC, DDC, or IRC. The lack of labelling of LC with monoclonal anti-C3b receptor antibody, and polyclonal antiserum recognizing C3b, C3bi, and C3d receptors strongly indicate that the EAC-rosetting of LC previously described is not due to the presence of C3 receptors on these cells. Alternatively, LC may express C3 receptor molecules different from those previously identified (C3b, C3bi, and C3d).

Metallothionein expression in basaloid proliferations overlying dermatofibromas and in basal cell carcinomas

Basaloid proliferations overlying dermatofibromas which morphologically resemble superficial basal cell carcinomas have been interpreted as both reactive/regressive and frankly malignant. Metallothioneins (MTs) are low‐molecular‐weight proteins with a selective binding affinity for heavy metal ions. MTs has been proposed to represent a biological marker of carcinogenesis and, in a variety of human tumours, a correlation between immunohistochemically overexpresstion of MT and aggressive clinical behaviour has been shown. In order to clarify the nature of basaloid proliferations overlying dermatofibromas, we examined, immunohistochemically, 10 dermatofibromas with overlying simple hyperplasia, 16 dermatofibromas with overlying basaloid proliferation, and 35 basal cell carcinomas, for expression of MT.

p53 protein expression in cutaneous T-cell lymphomas

p53 is an oncosuppressor gene located on chromosome 17p. Point mutations of the p53 gene are seen frequently in human malignancies, and are closely associated with malignant transformation under in vitro conditions. Mutated p53 protein shows a slow cell turnover rate, and accumulates in cells at the nuclear and/or cytoplasmic level. As a result, mutated p53 protein can be detected more readily by immunohistology than the wild‐type protein. In this study, we used a monoclonal anti‐p53 antibody (clone D07) to examine the expression of p53 protein in 25 cutaneous T‐cell lymphomas (CTCL) of low‐ and high‐grade malignancy, i.e. mycosis fungoides (n = 6), Sézarys syndrome (n = 2), and large cell lymphomas of pleomorphic (n = 14) or anaplastic (n= 3) subtype. The results showed that easily detectable p53 protein was present in many of the neoplastic cells in half of the high‐grade lymphomas. In contrast, in the low‐grade lymphomas no, or only very few, p53‐positive neoplastic cells could be detected. These findings suggest that molecular and/or genetic alterations of p53 may be implicated in the pathogenesis of high‐grade CTCL, but are unlikely to be of critical importance in low‐grade CTCL.

Immunohistological analysis of the lymphoid infiltrate in cutaneous malignant melanomas

The immunological phenotypes of the lymphoid cells in 39 cutaneous malignant melanomas have been investigated by staining cryostat sections with a panel of 20 monoclonal antibodies against lymphoid cells and their subsets. Staining was performed by the alkaline phosphatase: anti-alkaline phosphatase (APAAP) method in which the substrate label (red) is easily distinguishable from melanin. The lymphoid infiltrates had an essentially identical composition in all cases, consisting of T-lymphocytes associated with both Langerhans cells and HLA-DR-positive tissue macrophages. B-lymphocytes and natural killer cells were either absent or only present in low numbers. The ratio between T8 (suppressor/cytotoxic) and T4 (helper/inducer) lymphocytes varied and showed no correlation with melanoma subtype, level of invasion or magnitude of lymphocytic response. Examination for markers associated with T-cell activation and/or with cell proliferation revealed that all lesions contained HLA-DR-positive T-lymphocytes, whereas expression of the transferrin receptor and the interleukin-2 receptor (Tac-antigen) occurred mainly in melanomas with a significant inflammatory infiltrate. These data support the concept that malignant melanomas are capable of evoking autologous T-cell immune reactions.

Malignant melanoma of the skin in children (0 to 14 years of age) in Denmark, 1943-1982.

A total of 63 cases of cutaneous malignant melanoma in children have been reported to the Danish Cancer Registry during the 40-year period from 1943-1982. In order to describe the true incidence of childhood melanoma in Denmark, a clinical and pathological evaluation was performed. Not surprisingly we found that childhood melanomas were gravely overdiagnosed in Denmark. Nine cases of childhood melanoma were identified in our material. Seven of these were aged 10 to 14 years. Two of the tumours had developed in congenital giant naevi. The crude incidence rate was estimated to be between 0.24×10-6 and 0.32×10-6. In Denmark this corresponds to one new case of childhood melanoma every 3 to 4 years.

Apoptosis-related genes and proteins in Hodgkin's disease.

During recent years it has become increasingly evident that L&H cells in nodular lymphocytic predominance (LP) Hodgkins disease (HD) and Hodgkin and Reed‐Sternberg (H‐RS) cells in approximately half the cases of classical HD originate from B‐lymphocytes, and that H‐RS cells in most of the remaining cases of classical HD express a null phenotype. The pathogenesis of HD is unknown. An association with Epstein‐Barr virus (EBV) has been suggested and there are also indications that genes involved in programmed cell death (apoptosis) may be implicated. In this study, the expression of four apoptosis‐related proteins (bcl‐2, bcl‐x, bax and p53) in 53 cases of HD was examined and the data were correlated with the genotype, the EBV status and the phenotype (B, T or null) of the neoplastic cells. The H‐RS cells expressed a B‐cell phenotype in 3/3 cases of nodular LP and in 19/50 (38%) cases of classical HD. The remaining cases showed a null‐cell phenotype in 29/50 (58%) and a T‐cell phenotype in 2/50 (4%). EBV was more often positive in B (14/19, 74%) than in null (7/29, 24%) type HD. The H‐RS cells were bcl‐2‐positive in 19/53 (36%), bcl‐x‐positive in 17/53 (32%), bax‐positive in 1/53, and p53‐positive in 41/53 (77%) cases. No relationship was found between bcl‐2 expression and EBV status, or between bcl‐2 and bcl‐x expression. A t(14;18) translocation was seen in 2 of 34 cases. P53 point mutations were not detected. Our findings indicate that nodular LP and classical HD originate from B‐cells in a high proportion of cases. They also suggest a role for bcl‐2, bcl‐x and p53 in tumorigenesis. The pathogenesis is not known at this stage.

Bcl‐2 overexpression in basaloid proliferations overlying dermatofibromas and basal cell carcinomas

Basaloid proliferations overlying dermatofibromas resembling superficial basal cell carcinomas have been interpreted both as reactive/regressive and frankly malignant. Basal cell carcinoma is a slow‐growing tumour, which so far has been regarded as an actively proliferating lesion with a high apoptotic activity. We examined immunohistochemically 6 dermatofibromas with overlying simple hyperplasia, 12 dermatofibromas with overlying basaloid proliferations, and 24 basal cell carcinomas for expression of Ki‐67 protein and bcl‐2 protein. The Ki‐67 labelling index represents an estimate of proliferative activity. Bcl‐2 protein suppresses apoptosis. The Ki‐67 labelling indexes of basaloid proliferations, basal cell carcinomas, and normal epidermis were similar (11–15%, p<0.05, Mann‐Whitney test). Bcl‐2 protein was expressed in all cells of basaloid proliferations, similar to the expression pattern in basal cell carcinomas. We suggest that basaloid proliferations overlying dermatofibromas might have achieved a phenotype that equals an early stage of BCC carcinogenesis.

P53 protein expression in Hodgkin's disease

P53 is an oncosuppressor gene which is located on chromosome 17. Mutations of the p53 gene are closely associated with malignant transformation under in vitro conditions and are the most common genetic alteration in human malignancy. Unlike normal p53 protein which is unstable and usually cannot be detected by immunohistology, mutated p53 shows a decreased cell turnover rate and overexpression as compared with the wild‐type protein. In this study a panel of four anti‐p53 antibodies (PAb240, PAb421, PAb1801 and DO7) was applied to 52 cases of Hodgkins disease: three cases of nodular lymphocytic predominance (LP), 33 cases of nodular sclerosis (NS), and 16 cases of mixed cellularity (MC). The results show that 53 protein is present in the Hodgkins‐ and Reed‐Sternberg cells in 82% of NS and 94% of MC, but not in nodular LP. It is suggested that mutations of the p53 gene and loss of normal p53 function are frequent in Hodgkins disease and may be implicated in the pathogenesis of this disease.