Giovanni Roti

Quantitative assessment of minimal residual disease in acute myeloid leukemia carrying nucleophosmin (NPM1) gene mutations

Mutations in exon 12 of the nucleophosmin (NPM1) gene occur in about 60% of adult AML with normal karyotype. By exploiting a specific feature of NPM1 mutants, that is insertion at residue 956 or deletion/insertion at residue 960, we developed highly sensitive, real-time quantitative (RQ) polymerase chain reaction (PCR) assays, either in DNA or RNA, that are specific for various NPM1 mutations. In all 13 AML patients carrying NPM1 mutations at diagnosis, cDNA RQ-PCR showed >30 000 copies of NPM1-mutated transcript. A small or no decrease in copies was observed in three patients showing partial or no response to induction therapy. The number of NPM1-mutated copies was markedly reduced in 10 patients achieving complete hematological remission (five cases: <100 copies; five cases: 580–5046 copies). In four patients studied at different time intervals, the number of NPM1 copies closely correlated with clinical status and predicted impending hematological relapse in two. Thus, reliable, sensitive RQ-PCR assays for NPM1 mutations can now monitor and quantify MRD in AML patients with normal karyotype and NPM1 gene mutations.

Cytoplasmic nucleophosmin in myeloid sarcoma occurring 20 years after diagnosis of acute myeloid leukaemia.

Falini and colleagues reported that 35% of adults with acute myeloid leukaemia (AML) carry mutations at exon 12 of the nucleophosmin gene (NPM1), which leads to the formation of a C-terminal nuclear-export signal and mutations at tryptophans 288 and 290 that cause aberrant accumulation of nucleophosmin (NPM) in the cytoplasm. Mutation of NPM1 at exon 12 is the genetic lesion that arises most specifi cally and frequently in adults and children with AML who have a normal karyotype. These fi ndings have been confi rmed in about 1000 patients with AML. Leukaemia with cytoplasmic (ie, mutated) NPM—called NPMc+ AML— has distinct biological and clinical features, including frequent association with FAB (French American British) M4 and M5 morphology, CD34 and CD133 negativity, and high frequency of FLT3 mutations. In AML with normal karyotype, patients with mutations in NPM1 (ie, those who are NPMc+) have a distinct geneexpression profi le, a better response to induction treatment, and increased survival compared with those without mutations in NPM1 (ie, NPMc–). Here, we report, to our knowledge for the fi rst time, a patient with NPMc+ myeloid sarcoma of the skin presenting 20 years after diagnosis of AML. In 1984, a 24-year-old woman was admitted to the Haematology Unit, Pisa General Hospital, Italy, because of leucocytosis (white-cell count 35 000×106 cells/L, 40% blasts), tonsil and gum hyperplasia, and enlarged lymph nodes in the axillary and inguinal regions. Bone-marrow aspirate showed infi ltration by more than 90% leukaemic blasts that were positive for alfa-naphthylacetate esterase, myeloperoxidase, and naphthol AS-D chloro-acetate esterase, and negative for periodic acid Schiff ’s stain. The patient was diagnosed with AML-M4 according to WHO classifi cation; cytogenetic analyses were not done. The patient was treated with 1·5 mg/kg daunorubicin intravenously on day 1, 1·5 mg/kg cytarabine every 12 h on days 1–5, 1·5 mg/kg tioguanine every 12 h on days 1–5, and 1·5 mg/kg etoposide every 12 h on days 6–10. Bone-marrow aspirate showed the patient achieved complete haematological remission, and a second course of the above regimen was given as consolidation treatment. After refusing further treatment, the patient remained in continuous complete haematological remission over a 20-year follow-up. In February, 2004, the patient was readmitted to Pisa Hospital because of multiple, infi ltrating cutaneous lesions on the head and back. Blood-cell counts were normal. Marginal-zone B-cell lymphoma was diagnosed on two skin biopsies. The patient was treated with 25 mg oral prednisolone a day for 30 days. The disease progressed, with cutaneous lesions extending from the head (fi gure 1A) to the arms and legs. A third skin Lancet Oncol 2006; 7: 350–52

Acute lymphoblastic leukaemia in Noonan syndrome

Smulders, C., Persky, N., Grompe, M., Joenje, H., Pals, G., Ikeda, H., Fox, E.A. & Andrea, A.D. (2002) Biallelic inactivation of BRCA2 in Fanconi anemia. Science, 297, 606–609. MacMillan, M.L., Auerbach, A.D. & Wagner, J.E. (2005) Risk of malignancy in patients with biallelic BRCA2 mutations. Pediatric Blood & Cancer, 44, 539–540. Rosenberg, P.S., Greene, M.H. & Alter, B.P. (2003) Cancer incidence in persons with Fanconi anemia. Blood, 101, 822–826.

Different genomic imbalances in low- and high-grade HCV-related lymphomas.

Chronic infection with hepatitis C virus (HCV) is related to monoclonal B-cell lymphoproliferative disorders including a benign monoclonal lymphoproliferation such as type II mixed cryoglobulinemia, and B-cell non-Hodgkins lymphomas (NHL).

Cytogenetic/mutation profile of chronic lymphocytic leukemia/malignant melanoma collision tumors of the skin

BackgroundCollision tumors are rare entities that consist of two histologically distinct tumor types arising in the same anatomic site. An association between chronic lymphocytic leukemia (CLL) and malignant melanoma (MM) has been already described. Up to now, they have been documented only at positive regional lymph nodes while we focused on collision tumor in a skin lesion.Case presentationWe characterized the genomic profile of a skin CLL/MM collision tumor in a patient with a 9-years story of CLL. Typical high-grade genomic biomarkers featured the CLL: the immunoglobulin heavy variable genes were unmutated; a clonal del(11q), involving ATM and BIRC3, was present in the peripheral blood (PB) and skin lesion, while a subclonal large del(13q)/D13S319-RB1 was detected only in the PB. Interestingly, the del(13q) clone, increased from 10% to 46% from diagnosis to relapse. NOTCH1, SF3B1, and TP53 were wild type. The MM lesion carried a BRAFV600E and a TERT promoter mutation.As the family story was consistent with a genetic predisposition to cancer, we performed mutational analysis of genes involved in familial melanoma and CLL, and of BRCA1 and BRCA2. No germinal mutation known to predispose to CLL, MM, or breast cancer was found. Interestingly, conventional cytogenetic detected a constitutional t(12;17)(p13;p13).ConclusionsOur data are consistent with distinct genetic landscape of the two tumors which were characterized by specific disease-related abnormalities. CLL cells carried poor prognostic imbalances, i.e. large deletions of the long arm of chromosomes 11 and 13, while in MM cells two functionally linked mutations, i.e. BRAFV600E and a TERT promoter occurred. Although, known germline variations predisposing to MM and/or CLL were ruled out, genetic counseling suggested the proband family was at high risk for MM.