A prospective multicenter study was performed to investigate the clinical and molecular results of intensified double induction therapy including high-dose cytarabine (ara-C) in combination with ATRA in newly diagnosed acute promyelocytic leukemia (APL), followed by consolidation and 3 years maintenance therapy.

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The genomic breakpoints in the t(15;17)(q22;q21), associated with acute promyelocytic leukemia (APL), are known to occur within three different PML breakpoint cluster regions (bcr) on chromosome 15 and within RARA intron 2 on chromosome 17; however, the precise mechanism by which this translocation arises is unclear. To clarify this mechanism, we (i). assembled the sequence of RARA intron 2, (ii). amplified and sequenced the genomic PML-RARA junction sequences from 37 APL patients, and (iii). amplified and sequenced the reverse RARA-PML genomic fusion in 29 of these cases. Three significant breakpoint microclusters within RARA intron 2 were identified, suggesting that sequence-associated or structural factors play a role in the formation of the t(15;17). There was no evidence that the location of a breakpoint in PML had any relationship to the location of the corresponding breakpoint in RARA. Although some sequence motifs previously implicated in illegitimate recombinations were found in the microcluster regions, these associations were not significant. Comparison of forward and reverse genomic junctions revealed microhomologies, deletions, and/or duplications of either gene in all but one case, in which a complex rearrangement with inversion of the PML-derived sequence was found. These findings are consistent with the hypothesis that the t(15;17) occurs by nonhomologous recombination of DNA after processing of the double-strand breaks by a dysfunctional DNA damage-repair mechanism.

The quality of cervical histopathology is critical to cervical cancer prevention, cancer treatment, and research programs. On the basis of the histology results further patient management is determined. However, the diagnostic interpretation of histologic hematoxylin-eosin (H&E)-stained slides is affected by substantial rates of discordance among pathologists. Overexpression of the cyclin-dependent kinase inhibitor p16INK4a, a cell cycle regulating protein, has been shown to be strongly correlated with dysplastic lesions of the cervix uteri. In this study, we assessed whether p16INK4a immunohistochemistry may increase the performance of pathologists in diagnosing squamous lesions in cervical punch and cone biopsies. When using a consecutive p16INK4a-stained slide in conjunction to the H&E-stained slide, interobserver agreement between 6 pathologists improved significantly for both cervical punch and cone biopsies (P < 0.001). For punch biopsies (n = 247), kappa value increased from 0.49 (moderate agreement) to 0.64 indicating substantial agreement, and interobserver agreement for cone biopsies (n = 249) improved from 0.63 (conventional H&E slide reading) to 0.70 when H&E-stained slides were read conjunctively with p16INK4a-stained slides. In comparison to a common consensus diagnosis established by 3 independent experts, 4 pathologists reached an improvement with the conjunctive p16INK4a test, 2 of them showing significantly better agreement (P < 0.001 and P = 0.002, respectively), p16INK4a immunohistochemistry as an adjunct to conventional H&E-stained specimens thus contributes to a more reproducible diagnosis of cervical intraepithelial neoplasia and may be a valuable aid for the interpretation of cervical histology.

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Cyclin A is a cell cycle regulatory protein that functions in mitotic and S phase control in mammalian cells. However, in contrast to other G 1 phase regulatory proteins, such as cyclin D, retinoblastoma protein and p16 INK4A , cyclin A seems not to be commonly involved in tumorigenesis. Recently, a second human cyclin A -cyclin A1 -has been identified. In contrast to cyclin A which is expressed throughout embryonic development and in adult tissue, the expression of cyclin A1 has been reported to be restricted to embryonic and germ line cells. We have confirmed the absence of cyclin A1 mRNA from normal peripheral blood leukocytes of seven healthy donors by single step reverse transcriptase-polymerase chain reaction (RT-PCR). Furthermore, we have examined the expression of cyclin A1 mRNA in 173 peripheral blood samples of 162 patients with various hematological malignancies. Cyclin A1 mRNA was detectable in 11 of 11 patients with acute myeloid leukemia, three of three patients with acute biphenotypic leukemia, eight of eight patients with myelodysplastic syndrome, 59 of 69 patients with chronic myelogenous leukemia (CML) at diagnosis, 13 of 15 patients with CML in blastic transformation, 10 of 18 patients with chronic lymphocytic leukemia, two of nine patients with essential thrombocythemia, and only two of 10 patients with acute lymphoblastic leukemia (ALL) with both cyclin A1 RT-PCR positive ALL leukemias being undifferentiated relapses. In addition, cyclin A1 mRNA was found in one of six leukapheresis products, harvested from individuals without hematological disorders. Taken together, cyclin A1 is expressed in the majority of myeloid and undifferentiated hematological malignancies as well as in normal hematopoietic progenitor cells. We conclude that cyclin A1, a protein potentially involved in G 1 /S phase progression of immature cells, might be necessary for proliferation of early hematopoietic progenitor cells and their leukemic counterparts being blocked at that stage of differentiation.

A substantial minority of patients with chronic myelogenous leukemia (CML) achieve a complete response (CR) to treatment with interferon- (IFN), defined as the disappearance of Philadelphia chromosome-positive metaphases. Currently it is unclear how long IFN treatment should be continued for such patients. We used a competitive reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify levels of BCR-ABL transcripts in 297 peripheral blood specimens collected from 54 patients who had achieved CR with IFN. The median duration of observation was 1.9 years (range, 0.3-11.0 years). Total ABL transcripts were quantified as internal control and results were expressed as the ratio BCR-ABL/ABL. All 54 patients had molecular evidence of residual disease, although 3 patients were intermittently PCR negative. The median BCR-ABL/ABL ratio at the time of maximal response for each patient was 0.045% (range, 0%-3.6%). During the period of observation 14 patients relapsed, 11 cytogenetically to chronic phase disease and 3 directly to blastic phase. The median ratio of BCR-ABL/ABL at maximal response was significantly higher in patients who relapsed than in those who remained in CR (0.49% versus 0.021%,P &lt; 0.0001). Our findings show that the level of residual disease falls with time in complete responders to IFN, but molecular evidence of disease is rarely if ever eliminated. The actual level of minimal residual disease correlates with the probability of relapse. We suggest that for patients who reach CR, IFN should be continued at least until relatively low levels of residual leukemia are achieved. (Blood. 2000;95:62-66)