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: Pooled urine samples of patients with BTG (n=10), patients with PTC (n=9) and healthy controls (n=10) were subjected to iTRAQ analysis and immunoblotting.
RESULTS: The ITRAQ analysis of the urine samples detected 646 proteins, 18 of which showed significant altered levels (p<0.01; fold-change>1.5) between patients and controls. Whilst four urinary proteins were commonly altered in both BTG and PTC patients, 14 were unique to either BTG or PTC. Amongst these, four proteins were further chosen for validation using immunoblotting, and the enhanced levels of osteopontin in BTG patients and increased levels of a truncated gelsolin fragment in PTC patients, relative to controls, appeared to corroborate the findings of the iTRAQ analysis.
CONCLUSION: The data of the present study is suggestive of the potential application of urinary osteopontin and gelsolin to discriminate patients with BTG from those with PTC non-invasively. However, this needs to be further validated in studies of individual urine samples.
METHODS: A group of 33 healthy children, aged from 5 years 9 months-12 years 4 months (mean ± SD = 8.83 ± 1.92 years), was recruited. Their otolith saccular function was assessed using 750 Hz tone burst for cVEMPs (with ER3A insert phone), while their utricular function was assessed using Brüel & Kjaer Mini-shaker Type 4810 (Naerum, Denmark) for oVEMPs.
RESULTS: For cVEMPs, the mean value of P13 latency, N23 latency, P13-N23 interamplitude and asymmetry ratio were 12.62 ± 1.38 ms, 19.85 ± 1.95 ms, 92.47 ± 50.35 μV and 14.03 ± 9.75%, respectively. For oVEMPs, the mean value of N10 latency, P15 latency, N10-P15 interamplitude and asymmetry ratio were 9.23 ± 1.07 ms, 14.41 ± 1.04 ms, 10.32 ± 5.65 μV and 15.84 ± 11.49%, respectively. Two-way ANOVA analysis found that ear laterality and gender had no significant effect on all cVEMPs and oVEMPs parameters. No significant correlation was found between age and all VEMPs parameters.
CONCLUSIONS: The normative data for cVEMPs and oVEMPs obtained in this study can be used as a guide by health professionals to assess saccular and utricular functions among children age from 5 to 12 years of age.