Azma Rz

Evaluation of Glucose-6-phosphate dehydrogenase stability in stored blood samples

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is the commonest cause of neonatal jaundice in Malaysia. Recently, OSMMR2000-D G6PD Assay Kit has been introduced to quantitate the level of G6PD activity in newborns delivered in Universiti Kebangsaan Malaysia Medical Centre (UKMMC). As duration of sample storage prior to analysis is one of the matters of concern, this study was conducted to identify the stability of G6PD enzyme during storage. A total of 188 cord blood samples from normal term newborns delivered at UKMMC were selected for this study. The cord bloods samples were collected in ethylene-diamine-tetra-acetic acid (EDTA) tubes and refrigerated at 2-8 °C. In addition, 32 out of 188 cord blood samples were spotted on chromatography paper, air-dried and stored at room temperature. G6PD enzyme activities were measured daily for 7 days using the OSMMR2000-D G6PD Assay Kit on both the EDTA blood and dried blood samples. The mean value for G6PD activity was compared between days of analysis using Student Paired T-Test. In this study, 172 out of 188 cord blood samples showed normal enzyme levels while 16 had levels corresponding to severe enzyme deficiency. The daily mean G6PD activity for EDTA blood samples of newborns with normal G6PD activity showed a significant drop on the fourth day of storage (p < 0.005) while for samples with severely deficient G6PD activity, significant drop was seen on third day of storage (p = 0.002). Analysis of dried cord blood showed a significant reduction in enzyme activity as early as the second day of storage (p = 0.001). It was also noted that mean G6PD activity for spotted blood samples were lower compared to those in EDTA tubes for all days (p = 0.001). Thus, EDTA blood samples stored at 2-8 °C appeared to have better stability in terms of their G6PD enzyme level as compared to dried blood samples on filter paper, giving a storage time of up to 3 days.

The Msi2 protein expression positive correlation with favorable cytogenetics findings in AML

Acute myeloid leukaemia (AML) is the most common subtype of acute leukaemias with a poor outcome. Msi2 protein is a newly discovered prognostic marker and it has been considered as a new target for therapy in AML. The study of Msi2 protein expression in AML cases has not been performed in Malaysia, to date. The main aim of the present study was to observe the expression of Msi2 protein in AML patients by immunohistochemistry (IHC) and to correlate its expression with the well-established prognostic and clinical parameters in AML as well as the overall survival (OS). Sixty four bone marrow trephine biopsy sections were immunostained for Msi2 protein. The percentage of blasts with positive reaction and the intensity of the cytoplasmic and nuclear staining were evaluated. The expression of Msi2 protein was found in 95.3% cases with Msi2 pattern varying between the cases. In 71.9% of cases, the blasts showed total cellular positivity and 23.4% cases showed only cytoplasmic positivity. Majority showed high expression of Msi2 for cytoplasmic staining. Interestingly, there was significant correlation between total cellular staining and the intermediate cytogenetic subgroup (P= 0.04). In conclusion, the results showed that the majority of the patients had high expression of Msi2 but this did not correlate to OS. However, the Msi2 expression correlated to the cytogenetic findings. The results suggest future extensive research to be conducted in order to ascertain the exact role of Msi2 positive blast cells in AML in our population and their association with prognosis and outcome.

Comparison of protein-based cell-of-origin classification to the Lymph2Cx RNA assay in a cohort of diffuse large B-cell lymphomas in Malaysia

Aims The cell of origin (COO) based molecular characterisation into germinal centre B-cell-like (GCB) and activated B-cell-like (ABC) subtypes are central to the pathogenesis and clinical course in diffuse large B-cell lymphoma (DLBCL). Globally, clinical laboratories employ pragmatic but less than ideal immunohistochemical (IHC) assay for COO classification. Novel RNA-based platforms using routine pathology samples are emerging as new gold standard and offer unique opportunities for assay standardisation for laboratories across the world. We evaluated our IHC protocols against RNA-based technologies to determine concordance; additionally, we gauged the impact of preanalytical variation on the performance of Lymph2Cx assay. Methods Diagnostic biopsies (n=104) were examined for COO classification, employing automated RNA digital quantification assay (Lymph2Cx). Results were equated against IHC-based COO categorisation. Assay performance was assessed through its impact on overall survival (OS). Results 96 (92%) informative samples were labelled as GCB (38/96; 40%) and non-GCB (58/96; 60%) by IHC evaluation. Lymph2Cx catalogued 36/96 (37%) samples as GCB, 45/96 (47%) as ABC and 15/96 (16%) as unclassified. Lymph2Cx being reference, IHC protocol revealed sensitivity of 81% for ABC and 75% for GCB categorisation and positive predictive value of 81% versus 82%, respectively. Lymph2Cx-based COO classification performed superior to Hans algorithm in predicting OS (log rank test, p=0.017 vs p=0.212). Conclusions Our report show that current IHC-based protocols for COO classification of DLBCL at UKM Malaysia are in line with previously reported results and marked variation in preanalytical factors do not critically impact Lymph2Cx assay quality.