METHODS: Fifty-three formalin-fixed, paraffin-embedded nasopharyngeal carcinoma tissue blocks were chosen for this study. The presence of Epstein-Barr virus (EBV) was determined by in situ hybridisation using an EBER probe. p53 protein expression was detected using immunohistochemistry. Simultaneously, amplifications by PCR were performed for p53 exons 5 to 8, followed by mutation screening via single strand conformation polymorphism (SSCP). Sequencing of all the four exons was performed in five samples with mobility shift. To rule out false negative results by SSCP, 13 samples with p53 overexpression and five samples with low p53 expression were randomly selected and sequenced.
RESULTS: There was no mutation found in exons 5 to 8 in all the samples despite 46 (87%) of them having high p53 levels. EBV was detected in 51 (96%) out of 53 samples. There was no statistically significant association between p53 expression level and EBV presence.
CONCLUSIONS: High-intensity staining for p53 by immunohistochemistry was common in our series of NPC tissue samples but was not associated with 'hot spot' mutations of exons 5-8 of the gene. We did not find a significant relationship between the expression level of p53 and presence of EBV. Our study confirms that mutation of the DNA-binding domain of p53 is rare in NPC.
METHODS: Surgical samples from seven patients with a total of 17 sequential biopsies were retrieved for the study of p53 gene expression using immunohistochemical stain, and gene status by PCR-SSCP for exons 5-8. The tumours were graded according to the WHO classification criteria. P53 was distinctly over-expressed in five transformed higher grade biopsies, and all except one showed electrophoretic mobility shift in PCR-SSCP analysis. Sequencing analysis revealed single nucleotide substitutions in three of four of these high-grade transformed cases with band shift (75%), whereas some other studies reported a lower frequency of 25-30%, and mobility shift result was found to correlate with P53 expression. Lower grade tumours without P53 over-expression did not demonstrate band shift, and sequencing analysis did not reveal mutations.
CONCLUSIONS: We demonstrated the feasibility of adopting PCR-SSCP for screening of p53 mutations in archival tissue samples in this study, and there is a strong correlation of p53 gene over-expression and mutation events in high-grade transformed tumours.
METHODS: A total of 66 cHL cases were retrieved from the archives. Expressions of CD30, CD40, CD95 and proliferation by Ki-67 expression were detected with an immunohistochemical staining method. Apoptosis index was assessed by in situ TUNEL staining technique on 30 randomly selected cases and the presence of EBV was determined by EBER in situ hybridisation.
RESULTS: Expression of CD30, CD40 and CD95 in the H/RS cells was observed in a high proportion of the cases (100, 93.9, 90.5%, respectively). There was no significant association or correlation of the expression of these molecules with the presence of EBV. Expression of CD40 was associated with expression of the proliferation marker Ki-67 (P=0.044), whereas strong (intermediate and high) expression of CD30 showed a significant correlation with proliferation in the EBV-negative cases only (P=0.025). No correlation was observed for the expression of CD30 and CD40 with apoptosis of the H/RS cells. The childhood cases showed weaker CD95 expression in the H/RS cells than the adult cases, and the expression of CD95 was weaker than that of CD40 in the childhood group.
CONCLUSIONS: Our results showed that CD30, CD40 and CD95 are highly expressed in the H/RS cells of the majority of cases of cHL. The expression patterns seem to be independent of EBV and do not correlate with apoptosis of the H/RS cells.
METHODS: Eighty consecutive muscle biopsies in the Department of Pathology, National University of Singapore, in the period 1978-2000, in which a clinical diagnosis of floppy or hypotonic infant was made, were reviewed.
RESULTS: The commonest cause of severe hypotonia in infancy was spinal muscular atrophy, which accounted for 33% of cases followed by congenital muscular dystrophy (13%). Eight cases (10%) of infantile type II glycogenosis (Pompe's disease) were encountered. There were seven cases of congenital myopathy, of which four were centronuclear myopathy, and one each of central core myopathy, nemaline myopathy and congenital fibre type disproportion. One case of centronuclear myopathy was associated with type I fibre smallness. Type II atrophy, which is generally considered a non-specific change, was encountered in five cases. Of interest is the relatively large number of muscle biopsies (29%) in which no significant pathological features were encountered at the light microscopic, histochemical as well as ultra-structural level.
CONCLUSIONS: The study has revealed a great variety of pathology affecting the muscle of children presenting as floppy infants or with hypotonia. The muscle diseases included spinal muscular atrophy, congenital muscular dystrophies, congenital myopathies and metabolic myopathies. However, 23 (29%) cases showed no significant pathology. For this group of floppy and hypotonic infants further studies are needed.
METHOD: Blood samples were obtained from 20 healthy blood donors, 30 RA patients who presented with anaemia and 30 patients who had pure iron deficiency anaemia (IDA). The samples were analysed for full blood count, iron, ferritin, transferrin, soluble transferrin receptor and prohepcidin.
RESULTS: The mean prohepcidin level in the control subjects was 256 microg/L. The prohepcidin level was significantly lower in IDA patients (100 microg/L; p < 0.0001) but not significantly different from that of control in RA patients (250 microg/L; p > 0.05). Higher serum soluble transferrin receptor (sTfR) levels were observed in IDA (p < 0.0001) but not in RA compared with that of control (p > 0.05). RA patients were divided into iron depleted and iron repleted subgroups based on the ferritin level. Prohepcidin in the iron depleted group was significantly lower than the iron repleted group and the control (p < 0.0001) and higher levels were observed in the iron repleted group (p < 0.01). sTfR levels in the iron depleted group were significantly higher than the control and the iron repleted patients (p < 0.001). In the iron repleted group, sTfR level was not statistically different from that of control (p > 0.05).
CONCLUSION: Serum prohepcidin is clearly reduced in uncomplicated iron deficiency anaemia. The reduced prohepcidin levels in the iron depleted RA patients suggests that there may be conflicting signals regulating hepcidin production in RA patients. In RA patients who have reduced hepcidin in the iron depleted group (ferritin <60 microg/L) where sTfR levels are increased suggests that these patients are iron deficient. Further studies with a larger cohort of patients are required to substantiate this point.
METHODS: Using a panel of antibodies to CD10, Bcl-6, MUM1 and CD138, consecutive cases of primary UAT DLBCL were stratified into subgroups of germinal centre B-cell-like (GCB) and non-GCB, phenotype profile patterns A, B and C, as proposed by Hans et al. and Chang et al., respectively. EBER in situ hybridisation technique was applied for the detection of EBV in the tumours.
RESULTS: In this series of 32 cases of UAT DLBCL, 34% (11/32) were GCB, and 66% (21/32) were non-GCB types; 59% (19/32) had combined patterns A and B, and 41% (13/32) had pattern C. Statistical analysis revealed no significant difference in the occurrence of these prognostic subgroups in the UAT when compared with series of de novo DLBCL from all sites. There was also no site difference in phenotype protein expressions, with the exception of MUM1. EBER in situ hybridisation stain demonstrated only one EBV infected case.
CONCLUSIONS: Prognostic subgroup distribution of UAT DLBCL is similar to de novo DLBCL from all sites, and EBV association is very infrequent.
METHODS: A total of 234 invasive cervical carcinomas (152 squamous cell carcinomas, 61 adenocarcinomas and 21 adenosquamous carcinomas) and 16 cervical intraepithelial neoplasia (CIN) I, six CIN II and 25 CIN III were immunohistochemically studied for p53.
RESULTS: p53 was detected more frequently in CIN and invasive carcinoma (100% of CIN I, 74.2% CIN II + III and 70.1% invasive carcinoma) compared with benign cervices (P< 0.001); however, only three squamous cell carcinomas, 11 adenocarcinomas and two adenosquamous carcinomas exhibited p53 expression in >75% of tumour nuclei. Six of the 11 adenocarcinomas and both adenosquamous carcinomas were poorly differentiated compared with one of the three squamous carcinomas. p53 immunoreactive cells were randomly distributed in invasive carcinoma, confined to the lower third of the epithelium in CIN I, reached the middle third in 20% of CIN II and upper third in 16.6% of CIN III.
CONCLUSIONS: Assuming that p53 immunoreactivity indicates gene mutation when the majority (> 75%) of neoplastic cells express p53, p53 mutations would seem uncommon in cervical carcinogenesis. Nonetheless, glandular malignancies, in particular poorly differentiated variants, may show a higher frequency of mutation. p53 was detected more frequently in CIN I compared with CIN II/III and invasive carcinoma which may be due to p53 protein degradation following interaction with high risk human papillomavirus E6 protein in CIN II/III and invasive carcinoma.