Expression of lung resistance protein and multidrug resistance-related protein (MRP1) in pediatric acute lymphoblastic leukemia.

Multidrug resistance (MDR) is a phenomenon by which cells become resistant to unrelated chemotherapeutic agents. The prognostic value that lung resistance protein (LRP) and multidrug resistance-related protein 1 (MRP1) have in the setting of pediatric acute lymphoblastic leukemia (ALL) is controversial. The aim of this study was to investigate the expression of LRP and MRP1 and effect on clinical outcome and prognosis. The mRNA expression of LRP and MRP1 were analyzed in leukemic blasts of 34 pediatric ALL patients. LRP and MRP1 mRNA expression were detected in 41.2% and 35.3%, respectively. Eleven (91.7%) of 12 patients without LRP achieved CR compared with 9 (50.0%) of 18 with LRP expression. Similarly, 11 (100%) of 11 patients without MRP1 expression achieved CR compared with 9 (47.4%) of 19 with MRP1 expression and higher LRP expression rate or MRP1 expression rate was present in patients with relapse than MDR genes negative patients. The expression of either of two genes was associated with poorer 2-year survival. Also, patients expressing both genes had poorer outcomes and had worse 2-year survival. We suggest that MDR expression affects complete remission and survival rates in ALL patients. Thus, diagnosis appears to provide prognostic information for pediatric ALL.

p.R672C mutation of MYH3 gene in an Egyptian infant presented with Freeman-Sheldon syndrome.

OBJECTIVE: To define the mutation type in a clinically suspected Egyptian child with Freeman-Sheldon syndrome (FSS); it involves certain skeletal malformations with some facial characteristics; skeletal malformations include camptodactyly with ulnar deviation, talipes equinovarus, while the facial characteristics include deep-sunken eyes with hypertelorism, long philtrum, small pinched nose and pursed mouth. METHODS: Amplification of exon 17 of the embryonic myosin heavy chain (MYH3) gene was done using one forward and two different reverse primers, and then the cleaned PCR product was sequenced. RESULT: A de novo missense mutation (c.2014C>T with replacement C > Y) in MYH3 gene leading to change of arginine at position 672 by cytosine in protein sequence. CONCLUSION: Mutation analysis remains to be the standard way for definitive diagnosis in FSS. The authors currently report, for the first time in an Egyptian infant aged 16 months who presented with FSS, a c.2014C>T missense mutation of MYH3 gene, with no family history or consanguinity.