Vimentin: an evaluation of its role as a tumour marker In this study we examined 198 sarcomas, 38 carcinomas, 13 'tumours with a spindle cell component' and 22 malignant melanomas with a commercial monoclonal virnentin antibody. All histopathological material was formalin fixed and paraffin embedded. The results show this antibody to be a sensitive and specific marker of mesenchymal derivation or differentiation. It is a useful tool in separating sarcomas from most carcinomas, and in separating malignant melanomas from carcinomas. When used in combination with a cytokeratin antibody it identifies carcinosarcomas and synovial sarcomas.

Two hundred and three sarcomas, 40 carcinomas, 10 carcinomas with spindle cell features, 27 malignant melanomas and one spindle cell melanoma were examined using CAM 5.2, a monoclonal antibody to cytokeratin. This antibody which was prepared against colorectal carcinoma cells and which identifies low molecular weight intermediate filament cytokeratin proteins is suitable for use in formalin fixed, paraffin embedded material. Seventeen of the 203 sarcomas showed positive staining. These included 15/21 synovial sarcomas, 1/5 epithelioid sarcomas and 1/18 malignant neural tumours. Five carcinosarcomas showed positive staining of their epithelial components but negative staining of their spindle cell components; three out of four pure spindle cell carcinomas stained positively; a metastasis from a spindle cell renal carcinoma was negative. A spindle cell thymoma also stained positively. Thirty-seven of the 40 carcinomas stained positively; the three negative carcinomas were a squamous cell carcinoma, a renal cell carcinoma and an oat cell carcinoma. All malignant melanomas were negative. These results are compared with those of other workers and the sensitivity and specificity of CAM 5.2 as an epithelial marker is assessed.

SUMMARY A commercially available polyclonal antiserum (Dakopatts) raised against bovine neuron specific enolase (NSE) was reacted with 197 sarcomas, 32 carcinomas, 11 carcinoid tumours and 20 malignant melanomas to assess its specificity for neuroendocrine tumours. All the tumours had been fixed in formalin and embedded in paraffin. Positive tumour cells were found in two of 11 squamous cell carcinomas, one of 11 adenocarcinomas, 10 of 10 oat cell carcinomas, 11 of 11 carcinoid tumours, 16 of 20 malignant melanomas, four of seven clear cell sarcomas, nine of 25 leiomyosarcomas, four of 22 rhabdomyosarcomas, one of seven angiosarcomas and one of 20 synovial sarcomas.Neuron specific enolase (NSE) (yy) is an isoenzyme of the glycolytic enzyme enolase.' It was first localised in neurones but was subsequently found in neuroendocrine derived cells throughout the body.2 3 The antibodies raised against this antigen are widely used as tumour markers of neuroendocrine derived neoplasms. Although certainly useful in this respect, no study has adequately examined the specificity of commercially available NSE antibodies for neuroendocrine tumours. This information is obviously essential if NSE is to be used as a reliable tumour marker. As staining for NSE using the immunocytochemical peroxidase-antiperoxidase (PAP) method can be technically quite difficult and as the reagents are expensive, it is important that the optimal staining methods are well documented and the pitfalls associated with using this reagent well publicised. With these factors in mind, this study examined 32 carcinomas, 11 carcinoid tumours, 20 malignant melanomas and 197 sarcomas using a polyclonal commercially available antibody (Dakopatts) to NSE. All tumours studied had been fixed in formalin and embedded in paraffin. Material and methodsThirty two carcinomas, 11 carcinoid tumours, 20 malignant melanomas and 197 sarcomas were Accepted for publication 14 May 1986 included in this study. All were fixed in neutral buffered formalin and all were embedded in paraffin. The sarcomas were obtained from the files of this hospital. The age of the blocks ranged from 1-28 years. All sarcomas were examined by Professor DH MacKenzie.4 These were diagnosed mainly on the basis of haematoxylin and eosin staining and nonimmunocytochemical special stains. In "difficult" tumours and where material was available electron microscopy was carried out. The remaining tumours were chosen retrospectively from the files of this hospital and ranged in age from 1-4 years.NSE antiserum (Dakopatts) consists of polyclonal antibodies raised against bovine NSE. Its reliability was initially tested on a series of positive controls (nerve bundles). The reagent was also tested at differing dilutions and at varying temperatures and on sections which had and had not been trypsinised. The staining procedure used was the peroxidaseantiperoxidase technique. The best and most reliable results were obtained without trypsinisation, using a dilution of 1/4000 with overnight incubation and continu...

The histogenesis of synovial sarcomas remains controversial. An origin from epithelium, synovium, or synovial-related cells and neural tissue has been advanced. Using a combination of a cytokeratin (epithelial marker) antibody and a vimentin (mesenchymal marker) antibody, this study suggests that a synovial sarcoma might be regarded as a carcinosarcoma. It also highlights the diagnostic utility of those antibodies in the diagnosis of synovial sarcomas.

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