Yoshihiro Hatta

Deletions of p15 and/or p16 genes as a poor-prognosis factor in adult T-cell leukemia.

PURPOSE To determine the frequency of the deletions of p15/p16 genes in adult T-cell leukemia (ATL) cells and to evaluate their value in the diagnosis of clinical subtypes of ATL patients and the prediction of their clinical outcome. MATERIALS AND METHODS Peripheral-blood samples from 114 patients with ATL were examined by Southern blot analysis. In five chronic-type patients who showed disease progression to acute type, serial samples also were examined. RESULTS Among 114 patients, 28 (24.6%) showed the deletions of p15 and/or p16 genes. The results were well correlated with the clinical subtypes. Patients with deleted p15 and/or p16 genes had significantly shorter survival times than the patients in whom both genes were preserved (P < .0001). A similar decline in survival time was observed in the analyses within the same subtypes. In multivariate analysis using the Cox proportional hazard model, the deletions of p15 and/or p16 genes emerged as an independent prognostic indicator. Moreover, three of the five chronic-type patients who progressed to acute type lost the p16 gene alone or both the p15 and p16 genes at their exacerbation phase. CONCLUSION The results suggest the following: (1) that the deletions of p15 and/or p16 genes play a key role in the progression of ATL; and (2) that these deletions are reliable prognostic factors that predict shortened survival times.

Role of tumor suppressor genes in the development of adult T cell leukemia/lymphoma (ATLL)

Adult T cell leukemia/lymphoma (ATLL) is one of the peripheral T cell malignant neoplasms strongly associated with human T cell leukemia virus type-I (HTLV-I). Although the viral transactivating protein Tax has been proposed to play a critical role in leukemogeneis as shown by its transforming activity in various experimental systems, additional cellular events are required for the development of ATLL. One of the genetic events in ATLL is inactivation of tumor suppressor genes. Among many candidates for tumor suppressor genes, the main genetic events have been reported to center around the cyclin-dependent kinase inhibitors ((CDKIs) p15INK4A, p16INK4B, p18INK4C, p19INK4D, p21WAF1, p27KIP1, and p57KIP2), p53 and Rb genes; all of them play a major regulatory role during G1 to S transition in the cell cycle. Acute/lymphomatous ATLL has frequent alterations of p15 (20%) and p16 (28–67%), while chronic/smoldering ATLL has fewer abnormalities of p15 (0–13%) and p16 (5–26%). Most of these changes are deletion of the genes; fewer samples have mutations. ATLL patients with deleted p15 and/or p16 genes have significantly shorter survival than those individuals with both genes preserved. Although genetic alterations of p18, p19, p21, p27 have rarely been reported, inactivation of these genes may contribute to the development of ATLL because low expression levels of these genes seem to mark ATLL. The p53 gene is mutated in 10–50% of acute/lymphomatous ATLL. Functional impairment of the p53 protein, even if the gene has wild-type sequences, has been suggested in HTLV-I infected cells. Each of these genetic events are mainly found in acute/lymphomatous ATLL, suggesting that alterations of these genes may be associated with transformation to an aggressive phenotype. The Rb tumor suppressor gene is infrequently structurally altered, but one half of ATLL cases have lost expression of this key protein. Notably, alterations of one of the CDKIs, p53 and Rb genes appear to obviate the need for inactivation of other genes in the same pathway. A novel tumor suppressor gene on chromosome 6q may also have a critical role in the pathogenesis of ATLL. Taken together, tumor suppressor genes are frequently altered in acute/lymphomatous ATLL and their alteration is probably the driving force fueling the transition from chronic/smoldering to acute/lymphomatous ATLL.

Pre-transplant imatinib-based therapy improves the outcome of allogeneic hematopoietic stem cell transplantation for BCR-ABL-positive acute lymphoblastic leukemia.

A high complete remission (CR) rate has been reported in newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) following imatinib-based therapy. However, the overall effect of imatinib on the outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is undetermined. Between 2002 and 2005, 100 newly diagnosed adult patients with Ph+ALL were registered to a phase II study of imatinib-combined chemotherapy (Japan Adult Leukemia Study Group Ph+ALL202 study) and 97 patients achieved CR. We compared clinical outcomes of 51 patients who received allo-HSCT in their first CR (imatinib cohort) with those of 122 historical control patients in the pre-imatinib era (pre-imatinib cohort). The probability of overall survival at 3 years after allo-HSCT was 65% (95% confidence interval (CI), 49–78%) for the imatinib cohort and 44% (95% CI, 35–52%) for the pre-imatinib cohort. Multivariate analysis confirmed that this difference was statistically significant (adjusted hazard ratio, 0.44, P=0.005). Favorable outcomes of the imatinib cohort were also observed for disease-free survival (P=0.007) and relapse (P=0.002), but not for non-relapse mortality (P=0.265). Imatinib-based therapy is a potentially useful strategy for newly diagnosed patients with Ph+ALL, not only providing them more chance to receive allo-HSCT, but also improving the outcome of allo-HSCT.

Central nervous system event in patients with diffuse large B-cell lymphoma in the rituximab era

Central nervous system (CNS) events, including CNS relapse and progression to CNS, are known to be serious complications in the clinical course of patients with lymphoma. This study aimed to evaluate the risk of CNS events in patients with diffuse large B‐cell lymphoma in the rituximab era. We performed a retrospective survey of Japanese patients diagnosed with diffuse large B‐cell lymphoma who underwent primary therapy with R‐CHOP chemoimmunotherapy between September 2003 and December 2006. Patients who had received any prophylactic CNS treatment were excluded. Clinical data from 1221 patients were collected from 47 institutions. The median age of patients was 64 years (range, 15–91 years). We noted 82 CNS events (6.7%) and the cumulative 5‐year probability of CNS events was 8.4%. Patients with a CNS event demonstrated significantly worse overall survival (P < 0.001). The 2‐year overall survival rate after a CNS event was 27.1%. In a multivariate analysis, involvement of breast (relative risk [RR] 10.5), adrenal gland (RR 4.6) and bone (RR 2.0) were identified as independent risk factors for CNS events. We conclude that patients with these risk factors, in addition to patients with testicular involvement in whom CNS prophylaxis has been already justified, are at high risk for CNS events in the rituximab era. The efficacy and manner of CNS prophylaxis in patients for each involvement site should be evaluated further. (Cancer Sci 2012; 103: 245–251)

Speciation of arsenic trioxide metabolites in peripheral blood and bone marrow from an acute promyelocytic leukemia patient

BackgroundSpeciation of arsenic trioxide (ATO) metabolites in clinical samples such as peripheral blood (PB) from acute promyelocytic leukemia (APL) patients has been conducted. However, speciation of arsenicals in bone marrow (BM) has not yet been performed. Profiles of arsenic speciation in plasma of BM were thus investigated and compared with those of PB plasma from a relapsed APL patient. The total arsenic concentrations in high molecular weight fraction (HMW-F) of BM and PB plasma were also determined.MethodsResponse assessment was evaluated by BM aspirate examination and fluorescence in situ hybridization analysis. The analyses of total arsenic concentrations and speciation were preformed by inductively coupled plasma mass spectrometry (ICP-MS), and high-performance liquid chromatography (HPLC)/ICP-MS, respectively.ResultsResponse assessment showed that the patient achieved complete remission. The total arsenic concentrations in BM plasma increased with time during the consecutive administration. The PB plasma concentrations of methylated arsenic metabolites substantially increased after the start of administration, while those of inorganic arsenic were still kept at a low level, followed by substantially increase from day-14 after administration. The arsenic speciation profiles of PB plasma were very similar to those of BM plasma. Furthermore, the total arsenic concentrations of HMW-F in BM plasma were much higher than those in PB plasma.ConclusionsThe behaviors of arsenic speciation suggested for the first time that arsenic speciation analysis of PB plasma could be predicative for BM speciation, and showed relatively higher efficiency of drug metabolism in the patient. These results may further provide not only significance of clinical application of ATO, but also a new insight into host defense mechanisms in APL patients undergoing ATO treatment, since HMW proteins-bound arsenic complex could be thought to protect BM from the attack of free arsenic species.

Frequent loss of heterozygosity in the region of the D7S523 locus in advanced ovarian cancer

Loss of heterozygosity (LOH) of the long arm of chromosome 7 occurs frequently in many types of primary cancers. We analyzed 22 primary ovarian cancers for LOH of chromosome arm 7q using a set of 16 microsatellite markers in order to determine the location of a putative tumor suppressor gene (TSG). Eleven samples (50%) showed LOH at least at one locus on chromosome arm 7q. We identified the smallest commonly deleted region to be at 7q31.1, which includes D7S523. LOH of chromosome arm 7q was more frequent in advanced stages (III–IV) (7/9, 78%) than in early stages (I–II) (4/13, 31%) of ovarian cancer (P<0.05). These data suggest that alteration of a TSG at 7q31.1 gene plays an important role in advanced ovarian cancer. Genes Chromosom. Cancer 19:1–5, 1997.

Ovarian cancer has frequent loss of heterozygosity at chromosome 12p12.3-13.1 (region of TEL and Kip1 loci) and chromosome 12q23-ter: evidence for two new tumour-suppressor genes.

Identification of the key genetic alterations leading to ovarian cancer is in its infancy. Polymerase chain reaction (PCR)-based analysis of loss of heterozygosity (LOH) is a powerful method for detecting regions of altered tumour-suppressor genes. Focusing on chromosome 12, we examined 23 ovarian cancer samples for LOH using 31 highly polymorphic microsatellite markers and found the chromosomal localization of two putative tumour-suppressor genes. Two commonly deleted regions were 12p12.3-13.1 in 6/23 (26%) and 12q23-ter in 7/23 (30%) samples. LOH on chromosome 12 was more common in late-stage ovarian carcinomas. The region of LOH at 12p12.3-13.1 includes the genes that code for the ETS-family transcriptional factor, known as TEL, and the cyclin-dependent kinase inhibitor, known as p27Kip1. Mutational analysis of both TEL and p27Kip1 using single-strand conformation polymorphism (SSCP) showed no abnormalities, suggesting that the altered gene in this region is neither of these genes. Taken together, our data suggest that new tumour-suppressor genes in the region of chromosomes 12p12.3-13.1 and 12q23-ter may be involved in the development of ovarian cancer.

Intravascular large B-cell lymphoma presenting with mass lesions in the central nervous system: A report of five cases

We have encountered five cases of intravascular large B‐cell lymphoma (IVL) presenting with central nervous system (CNS) mass lesions during their clinical course. The age of the patients ranged from 50 to 74 years and three patients were male. All of these cases histopathologically showed typical intravascular localization of the neoplastic cells in the initial biopsy specimens obtained from sites other than the CNS. Despite multiagent chemotherapy, patients suffered from single or multiple CNS mass lesions 5–44 months after the initial diagnosis of IVL, except for one case in which IVL and the CNS mass lesion were diagnosed at the same time. The subsequent biopsy and autopsy specimens obtained from the CNS mass lesions revealed diffuse infiltration of the tumor cells with perivascular spreading, but minimal or no intravascular components. Immunohistochemical analysis of intravascular tumor cells and CNS mass lesions revealed expression of CD20, CD79a, bcl‐2 and negative for CD3e and Epstein–Barr virus encoded RNA. The overall features of the CNS mass lesions were very similar to or indistinguishable from those of the primary CNS lymphomas. This implies that CNS mass lesions in the IVL cases can be correctly diagnosed only by careful attention to clinical and pathological findings. Moreover, there is the possibility that some cases previously diagnosed as primary CNS lymphomas may have include IVL cases. Further investigation is needed to explore this unusual phenomenon.

Alterations of the p16 (MTS1) Gene in Testicular, Ovarian, and Endometrial Malignancies

PURPOSE The p16 (MTS1) gene codes for a cyclin-dependent kinase inhibitor and may be a new tumor suppressor gene. It is frequently mutated in a variety of cell lines established from tumors. This is the first report of screening for alteration of the p16 gene in testicular, ovarian and endometrial malignancies. MATERIALS AND METHODS We examined alterations of p16 in 78 primary genital tumors (42 testicular, 21 ovarian and 15 endometrial cancers) and mononuclear cells from 2 patients with Lynch syndrome II as well as 5 testicular tumor cell lines by single-strand conformation polymorphism (SSCP) and Southern blot hybridization. RESULTS The DNA from the p16 gene of 2 testicular tumors (5%), an ovarian cancer (4%) and a testicular tumor cell line (20%) had altered migration in gel electrophoresis as shown by SSCP. Analysis of DNA sequence of these samples revealed a polymorphism at codon 140. Southern blot hybridization detected neither deletions nor rearrangements of the p16 gene in any of the samples. CONCLUSIONS Taken together, these results suggest that p16 alterations probably are not important for tumorigenesis of testicular, ovarian and endometrial tumors.

Infrequent microsatellite instability during the evolution of the myelodysplastic syndrome to acute myelocytic leukemia

Microsatellites are highly polymorphic, short-tandem repeat sequences dispersed throughout the genome. Instability of these repeat sequences at multiple gentic loci may result from mismatch repair errors and occur in hereditary nonpolyposis colorectal cancer and several other sporadic cancers, including chronic myelocytic leukemia as it progresses to blastic crisis. We investigated whether genetic instability occurred as myelodysplasia progressed to acute myelocytic leukemia. To this end, we studied microsatellite instability in 20 patients with myelodysplastic syndrome (MDS). These included five patients with refractory anemia (RA), three with refractory anemia with ringed sideroblast (RARS), nine with refractory anemia with excess blasts (RAEB) and three with chronic myelomonocytic leukemia (CMML). All of these patients transformed to acute myelocytic leukemia (AML) of various subtypes: three patients with M1, 11 with M2 and six patients with M4 (according to FAB classification). The DNA from both the MDS and AML phases of their disease was analyzed at 16 loci, and only four microsatellite instabilities were found in the 240 paired samples (1.6%) analyzed. These results indicate that mismatch repair errors such as microsatellite instability are not important in the evolution of MDS to AML.