Pediatric Hematology and Oncology, 26:48–56, 2009 Copyright C  Informa Healthcare USA, Inc. ISSN: 0888-0018 print / 1521-0669 online DOI: 10.1080/08880010802625530 EXPRESSION OF PTEN AND SHP1, INVESTIGATED FROM TISSUE MICROARRAYS IN PEDIATRIC ACUTE LYMPHOBLASTIC, LEUKEMIA Fredrika Gauffin, MD, PhD (Cand) ✷ Department of Clinical Science, Intervention and Technology (CLINTEC), Division of Pediatrics, Karolinska Institutet, Stockholm, Sweden Eva Diffner, PhD (Cand) ✷ Center for Molecular Pathology, Malm¨ o University Hospital, Malm¨ o, Sweden Bertil Gustafsson, MD, PhD ✷ Department of Pathology, Faculty of Health Sciences, Link¨ oping University Hospital, Sweden Ann Nordgren, MD, PhD ✷ Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Anette Gj ¨ orloff Wingren, PhD ✷ Department of Tumor Biology, Lund University, Malm¨ o University Hospital, Malm¨ o, Sweden Birgitta Sander, MD, PhD ✷ Department of Laboratory Medicine, Div of Pathology, Karolinska Institutet, Stockholm, Sweden Jenny Liao Persson, PhD ✷ Department of Laboratory Medicine, Division of Pathology, Lund University, Malm¨ o, Sweden Britt Gustafsson, MD, PhD ✷ Department of Clinical Science, Intervention and Technology (CLINTEC), Division of Pediatrics, Karolinska Institutet, Stockholm, Sweden ✷ PTEN and SHP1 are tumor suppressor genes involved in the regulation of cell cycle control and apoptosis. The authors investigated the protein expression of PTEN and SHP1, by immunohistochemistry in tissue microarrays from bone marrow samples in children, diagnosed with acute lymphoblastic leukaemia and nonmalignant controls. PTEN was overexpressed in diagnostic ALL samples, while SHP1 showed a low expression. Both proteins showed a significant difference in expression compared to nonmalignant controls. The roles of PTEN and SHP1 are not well investigated in pediatric leukemia and could in the future play a role as prognostic factors. Received 6 January 2009; Accepted 11 January 2009. Address correspondence to Britt Gustafsson, MD, Associate Professor, Department of Clinical Science, Intervention and Technology (CLINTEC) Karolinska Institutet, Division of Pediatrics B57, Karolinska University Hospital Huddinge, SE-141 86, Sweden. E-mail: britt.gustafsson@ki.se 48