Toshiya Okubo

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.

Myelomonoblastic leukaemia cells carrying the PEBP2β/MYH11 fusion gene are CD34+, c-KIT+ immature cells

To clarify the aspects affected by the PEBP2β/MYH11 fusion gene involved in the inv(16), we analysed immunophenotypes in myelomonoblastic leukaemias. We found high expressions of CD34 and c‐KIT antigens in myelomonoblastic cells from all patients carrying this fusion gene, including two with M4 and one CML blastic phase, in contrast to those with M4 without the fusion gene. These findings indicate that immunophenotyping is useful for detecting a leukaemia with the fusion gene in myelomonoblastic leukaemias and that the PEBP2β/MYH11 gene is involved in immature cells expressing CD34 and c‐KIT antigens.

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.

Detection of Epstein-Barr viral DNA in aggressive CD8+ T cell leukaemic cells

(70%)) were trisomic (three signals). A similar result \\’as obtained with the 1 5 Epo-independent colonies, of which fire (33,3‘%,) had two signals and 10 I66. i%)) had three signals. In each colony over 85% of the scorable cells showed the same chromosome 8 complenient. Examples of double labelled FISH and immuiiophenotyped ( K 1 0 + ) colony cells are shown in Figs I X (~po-stiniulateditrisomy 81 and 1B (Epo-independentldiploid chromosome 8). Statistical cornparisoii (Fisher’s Exact Test) of the proportion of Epoindependent/Epo stimulated colonies ( 104/291 I 36%) with the proportion of trisomy 8 positive Epo-stimulated colonies [ 14i20, i O % ) showed that it was likely that a significant number of the trisomy X colonies were Epo-dependent ( I’ < 0.00 3 ). PreiTious investigations in P\’ have demonstrated that normal cells coexist with the clonal population in these patients (Eaves & Eaves, 19 78: Adamson et al. 1980). and that their numbers appear to decline with the natural progression of the disease (Adamson c’t nl. 19 80). This latter study also concluded that the MPD erythroid clone was not restricted to the Epo-independent population. suggesting that the abnormal progenitor cells have a variable Epo requirement. The in-situ hybridization results of our study in this patient could he interpreted as confirming this, in that some of the colonies with trisomy 8 were clealy Epo-dependent. However. our additional finding that some of the Epoindependent colonies had a normal chroniosome 8 complement suggests that the trisomy 8 did not completely define the MPD clone. This w.ould most likely signify clonal evolution. the trisomy 8 being an additional abnormality that has occurred in a subpopulation of the original MPD clone. Alternatively. it could indicate that it is a secondary mutational event that has affected both hlPD and non-MPD cells. Although we consider this latter interpretation less likely. i t could he supported by a recent study of trisomy i in malignant gliomas in which it was found that some of both the neoplastic and non-neoplastic cells within the tumours showed this abnormality (Lindstroni et d . 19 9 1 ). Either of the es would explain our finding of Epo-independent (and therefore apparently myeloproliferatire) colonies without trisomy 8 in this patient. Further combined in-sitir hybridization/progenitor cell culture studies may help identify the role of trisomy 8 and British Juurnal of Haematology, 1992, 82

Oral melphalan, dexamethasone, and thalidomide for the treatment of refractory multiple myeloma.

We present a patient with refractory multiple myeloma who showed a good response to a combination therapy with oral melphalan, dexamethasone, and thalidomide (MDT). A 48-year-old woman with myeloma refractory to thalidomide, dexamethasone, and clarithromycin received 6 mg melphalan for 4 days every 6 weeks in combination with thalidomide (100 mg daily) and dexamethasone (5 mg daily for 2 days every week). Four months after the initiation of MDT therapy, a 78% reduction of monoclonal protein was achieved. Although the efficacy of oral MDT combination therapy in elderly patients with newly diagnosed myeloma has been reported, the present data demonstrate the effectiveness of MDT therapy for refractory myeloma and warrant further exploration with this MDT regimen to treat myeloma.