Mesenchymal and muscle-specific intermediate filaments (vimentin and Desmin) in relation to differentiation in childhood rhabdomyosarcomas

Evaluation of desmin as a diagnostic and prognostic marker of childhood rhabdomyosarcomas and embryonal sarcomas

“…The published literature indicates that desminpositivity in RMS is associated with cytological differentiation. Molenaar et al (1985) noted that the differences in staining observed between their poorly, moderately and well differentiated RMS reflected quantitative differences in the expression of desmin. Therefore, if desmin is utilised as a marker of myogenic differentiation, the results of this study would indicate that poorly differentiated rhabdomyosarcomas tend to have a better prognosis than well differentiated tumours.…”

“…Our desmin staining results are within the range reported in the literature where the expression of desmin has been shown to vary from 32 to 100 percent (see Table I). The variation in positivity may be partly accounted for by the use of different antibodies, the degree of differentiation of the tumours examined (de Jong et al 1985; Tsokos et al, personal communication; Molenaar et al, 1985) and the method of fixation and staining of the tumour specimens (Altmannsberger et al, 1985;Molenaar et al, 1985). It appears that formalin fixation may not be conducive to immunostaining for desmin, especially in poorly differentiated rhabdomyosarcomas.…”

“…It appears that formalin fixation may not be conducive to immunostaining for desmin, especially in poorly differentiated rhabdomyosarcomas. In their comparison of frozen with formalin fixed RMS, Molenaar et al (1985) concluded that the latter is inadequate for demonstrating minimal amounts of desmin. In the desmin positive tumours in our series, a higher proportion of well differentiated tumour cells stained for desmin whereas most of the poorly differentiated tumour cells were negative.…”

“…Essentially the procedure was same as the PAP procedure except the reagents substituted were a 1/20 dilution of normal rabbit serum, followed by a 1/10 dilution of desmin monoclonal antibody and finally by a 1/40 dilution of peroxidase conjugated rabbit anti-mouse immunoglobulin (Dakopatts). Kahn et al (1983) 8/25 32 Molenaar et al (1985) 17 The standard Kaplan and Meier statistical analysis (Kaplan & Meier, 1958) was used for calculating and projecting curves of overall survival. Statistical differences between the survival curves were analysed by the log rank test (Peto et al, 1977).…”

Auricular Embryonal Rhabdomyosarcoma

“…In this case there was expression of myoglobin but not desmin. The latter is generally found only in tumours with round rhabdomyoblasts or strap cells [8]. both of which were absent in this tumour.…”