Koyu Hoshino

The absence of the p15INK4B gene alterations in adult patients with precursor B-cell acute lymphoblastic leukaemia is a favourable prognostic factor.

Summary. We examined deletion and methylation of the p15INK4B(p15) and p16INK4A(p16) genes, using Southern blotting and methylation‐specific polymerase chain reaction (PCR), in 70 untreated adult patients with precursor B‐cell acute lymphoblastic leukaemia (PBC‐ALL) and analysed the relationship between their genetic changes and clinical outcome. Methylation and homozygous deletion of the p15 gene were detected in 30 (43%) and 18 (26%) patients, while those of the p16 gene were found in 16 (23%) and 11 (16%) patients respectively. Thirteen out of 17 patients with wild‐type p15 gene showed expression of p15 mRNA, whereas 31 out of 39 patients with alteration (deletion and methylation) of the p15 gene showed no p15 mRNA expression by reverse transcription–PCR, suggesting that alterations of the p15 gene are highly associated with loss of␣p15 mRNA expression. Disease‐free survival (DFS) at 4 years in patients with wild‐type p15 gene is 33%, compared with 4% of those with p15 gene alterations (P = 0·049). Multivariate analysis showed that the absence of p15 gene alterations was an independent significant favourable prognostic factor for longer DFS (P = 0·0001). These results suggest that alterations in the p15 but not p16␣gene can be used as a genetic prognostic indicator in PBC‐ALL.

Successful treatment of Aspergillus liver abscesses in a patient with acute monoblastic leukemia using combination antifungal therapy including micafungin as a key drug

While anti-cancer chemotherapy has improved the survival of patients with hematologic malignancies, it has also exposed such patients to the risk of life-threatening infection due to neutropenia. In intensive chemotherapy for leukemia, invasive aspergillosis resulting in death is infrequently observed. In such cases, aggressive diagnostic and therapeutic intervention is required. Herein, we report a case of Aspergillus liver abscesses in a patient with acute monoblastic leukemia. The patient presented with febrile neutropenia and concomitantly with an elevated serum β-d-glucan level during chemotherapy. The abscesses were finally diagnosed by liver biopsy. Although antifungal monotherapy of voriconazole or liposomal amphotericin B, both of which are recommended for invasive aspergillosis, showed a poor response, when combined with micafungin, an echinocandin, both had a highly favorable effect against the infection. Therefore, our clinical experience suggests that the serum test is useful for the rapid diagnosis of invasive aspergillosis, especially in deep tissues, and that combination antifungal therapy with micafungin should be considered when initial monotherapy for fungal infection shows an insufficient effect.

Long-term remission in an elderly patient with mantle cell leukemia treated with low-dose cyclophosphamide.

We present an elderly patient with mantle cell leukemia who was successfully treated with low‐dose cyclophosphamide (CY). A 76‐year‐old female was diagnosed as mantle cell leukemia based on abnormal lymphocytosis and splenomegaly without lymphadenopathy. She was orally treated with 50 mg of CY daily and had continuous remission over 4 years. Rearrangements of BCL1 and immunoglobulin heavy chain genes in the peripheral blood lymphocytes were detected at diagnosis, but not 1 or 4 years later. Further studies are required to confirm the role of low‐dose CY therapy for patients with mantle cell leukemia and lymphoma. Am. J. Hematol. 63:35–37, 2000.

Acute Myelomonoblastic Leukemia Carrying the PEBP2β/MYH11 Fusion Gene

As recurrent chromosome abnormalities in leukemia are highly associated with particular subtypes, the genetic events of specific chromosome alteration must be associated with leukemogenesis and characteristics of the disease. The chromosomal breakpoints involved in inv(16) and t(16;16) have been shown to generate the fusion gene PEBP2beta(CBFbeta)/MYH11. The PEBP2beta/MYH11 fusion transcripts in all 8 patients with M4Eo, 2 of 18 with M4, and one CML in the blastic phase were detected by using RT-PCR and Southern blotting. We demonstrated the marked expression of CD34 and c-KIT (CD117) antigens in myelomonoblastic leukemia cells from all patients carrying this fusion gene, which was in contrast to the patients with M4 but without the fusion gene. These results indicate that immunophenotypic analysis is useful for detection of leukemia with the fusion gene, and that the PEBP2beta/MYH11 fusion gene is involved in immature cells expressing CD34 and c-KIT antigens.

Regulation of AURKC expression by CpG island methylation in human cancer cells

AURKC, a member of the Aurora kinase gene family, is highly expressed in testis but is either moderately expressed or repressed in most somatic cells. Varying expression of AURKC has been observed in human cancers, but the underlying mechanisms of differential expression have been investigated only to a limited extent. We investigated the role of promoter CpG methylation in the regulation of AURKC gene expression in human cancer cells, in relation to a recently reported AURKC transcription repressor PLZF/ZBTB16, implicated in transformation and tumorigenesis. AURKC and PLZF/ZBTB16 expression profiles were investigated in reference to CpG methylation status on the AURKC promoter experimentally, and also in The Cancer Genome Atlas (TCGA) dataset involving multiple cancer types. AURKC promoter showed dense to moderate hypermethylation correlating with low to moderate expression of the gene in normal somatic cells and cancer cell lines, while testis with high expression revealed marked hypo-methylation. Treatment with the demethylating agent, 5-aza-dC, but not the histone deacetylase (HDAC) inhibitor, TSA, led to elevated expression in cancer cell lines, indicating that promoter DNA methylation negatively regulates AURKC expression. High expression of PLZF in PLZF-transfected cells treated with 5-aza-dC only partially repressed expression of AURKC despite 5-aza-dC also inducing elevated PLZF expression. Analyses of the TCGA data showed differential expression of AURKC in multiple cancer types and stronger correlation of AURKC expression with CpG methylation compared to PLZF levels. These findings demonstrate that differential promoter CpG methylation is an important mechanism regulating AURKC expression in cancer cells.