A human c-erbA oncogene homologue is closely proximal to the chromosome 17 breakpoint in acute promyelocytic leukemia.

A human cDNA library was screened for sequences homologous to the erbA gene of avian erythroblastosis virus (AEV). One such clone, cHerbA-1, was used to map the chromosomal location of highly homologous human sequences that were found to be present on chromosome 17 as judged by Southern blot screening of a panel of mouse-human hybrid cell lines segregating human chromosomes. cHerbA-1 was hybridized in situ to metaphase chromosomes from a normal male subject and from a female patient with an acute promyelocytic leukemia (APL) having the typical t(15;17) translocation. The results localized the cellular c-erbA sequences on chromosome 17 to the q21-q24 region of normal chromosomes and indicated that the c-erbA sequences remained on the 17q- chromosome in the APL cells, suggesting that they could be assigned to the 17(q21-q22) region. For additional data, we hybridized human neoplastic cells derived from a poorly differentiated acute leukemia carrying a t(17;21) translocation with thymidine kinase (TK)-deficient LMTK- mouse cells. A resulting hybrid, containing only the 21q+ chromosome, did not have human c-erbA sequences. Since the breakpoint on 17q in this translocation was similar to that in the APL t(15;17) translocation, this supported the assignment of c-erbA to the q21-q22 region of chromosome 17. The apparent close proximity of the c-erbA sequences to the chromosomal breakpoints in these two leukemias suggests a possible role for this oncogene homologue in the development of these neoplasms.     

Co-expression of two FAB-specific chromosome changes,t(15; 17) and t(8; 21), in a case of acute promyelocytic leukemia

 We describe a case of acute promyelocytic leukemia ANLL-M3 with association of t(15; 17) and t(8; 21) and various chromosomal aberrations. Clinically, immunologically, and morphologically, our patient fits the diagnosis of typical ANLL-M3. The co-existence of two specific FAB chromosomal translocations in a single leukemic clone is rare. The rarity of this association enhances the significance of this report. Received: 27 September 1995 / Accepted 13 March 1996     

Assessment of minimal residual disease in acute promyelocytic leukaemia with t(15;17) by chromosome painting

Abstract: To detect the minimal residual disease (MRD) in acute promyelocytic leukaemia patients treated with all-trans retinoic acid, we compared the sensitivity of metaphase fluorescence in situ hybridization (FISH) with conventional analysis of G-banded metaphases. 5 out of 6 patients studied at diagnosis showed the t(15;17) translocation. 4 out of 5 patients carrying t(15;17) achieved complete remission and conventional cytogenetic conversion. In 3 cases the whole chromosome painting (WCP) probe 17 discovered one normal chromosome 17 and two fragments indicative of t(15;17) persistence. The FISH-WCP technique seems to be highly sensitive and recommendable in monitoring leukaemias with specific chromosome rearrangements.     

Genetic analysis of the 15;17 chromosome translocation associated with acute promyelocytic leukemia.

Somatic cell hybrids have been constructed between a thymidine kinase-deficient mouse cell line and blood leukocytes from a patient with acute promyelocytic leukemia showing the 15q+;17q- chromosome translocation frequently associated with this disease. One hybrid contains the 15q+ translocation chromosome and very little other human material. We have shown that the c-fes oncogene, which has been mapped to chromosome 15, is not present in this hybrid and, therefore, probably is translocated to the 17q- chromosome. Analysis of the genetic markers present in this hybrid has enabled a more precise localization of the translocation breakpoints on chromosomes 15 and 17. Our experiments also have enabled an ordering and more precise mapping of several genetic markers on chromosomes 15 and 17.     

T(15;17) in acute promyelocytic leukemia is not associated with submicroscopic deletions on der(17)

We report a fluorescent in situ hybridization (FISH) study on 34 patients with acute promyelocytic leukemia. The study was designed to detect microdeletions in the derivative chromosome 17 which is the result of a reciprocal translocation t(15;17). No deletion was found.     

Clinical impact of FLT3 mutation load in acute promyelocytic leukemia with t(15;17)/PML-RARA

Background

Combined treatment with all-trans-retinoic acid and chemotherapy is extremely efficient in patients with acute promyelocytic leukemia with t(15;17)/PML-RARA, but up to 15% of patients relapse.

Design and Methods

To further clarify the prognostic impact of parameters such as FLT3 mutations, we comprehensively characterized the relation between genetic features and outcome in 147 patients (aged 19.7–86.3 years) with acute promyelocytic leukemia.

Results

Internal tandem duplications of the FLT3 gene (FLT3-ITD) were detected in 47/147 (32.0%) and tyrosine kinase domain mutations (FLT3-TKD) in 19/147 (12.9%) patients. FLT3-ITD or FLT3-TKD mutation status did not have a significant prognostic impact, whereas FLT3-ITD mutation load, as defined by a mutation/wild-type ratio of less than 0.5 was associated with trends to a better 2-year overall survival rate (86.7% versus 72.7%; P=0.075) and 2-year event-free survival rate (84.5% versus 62.1%, P=0.023) compared to the survival rates of patients with a ratio of 0.5 or more. Besides the t(15;17), an additional chromosomal abnormality was detected in 57 of 147 cases and did not show a significant impact on survival. White blood cell counts of 10×10⁹/L or less versus more than 10×10⁹/L were associated with a better 2-year overall survival rate (88.3% versus 69.4%, respectively; P=0.015), as was male sex (P=0.040). In multivariate analysis, only higher age had a significant adverse impact.

Conclusions

Prospective trials should further investigate the clinical impact of the FLT3-ITD/wild-type mutation load aiming to evaluate whether this parameter might be included in risk stratification in patients with acute promyelocytic leukemia.     

Molecular analysis of t(15;17) genomic breakpoints in secondary acute promyelocytic leukemia arising after treatment of multiple sclerosis

Therapy-related acute promyelocytic leukemia (t-APL) with t(15;17) translocation is a well-recognized complication of cancer treatment with agents targeting topoisomerase II. However, cases are emerging after mitoxantrone therapy for multiple sclerosis (MS). Analysis of 12 cases of mitoxantrone-related t-APL in MS patients revealed an altered distribution of chromosome 15 breakpoints versus de novo APL, biased toward disruption within PML intron 6 (11 of 12, 92% vs 622 of 1022, 61%: P = .035). Despite this intron spanning approximately 1 kb, breakpoints in 5 mitoxantrone-treated patients fell within an 8-bp region (1482-9) corresponding to the "hotspot" previously reported in t-APL, complicating mitoxantrone-containing breast cancer therapy. Another shared breakpoint was identified within the approximately 17-kb RARA intron 2 involving 2 t-APL cases arising after mitoxantrone treatment for MS and breast cancer, respectively. Analysis of PML and RARA genomic breakpoints in functional assays in 4 cases, including the shared RARA intron 2 breakpoint at 14 446-49, confirmed each to be preferential sites of topoisomerase IIalpha-mediated DNA cleavage in the presence of mitoxantrone. This study further supports the presence of preferential sites of DNA damage induced by mitoxantrone in PML and RARA genes that may underlie the propensity to develop this subtype of leukemia after exposure to this agent.     

Latent acute promyelocytic leukemia t(15;17)(q22;q12-21) and sarcoidosis: long-term cohabitation

The association of sarcoidosis with hematological malignancies is a well-known phenomenon. To our knowledge, we report the first case involving sarcoidosis and acute promyelocytic leukemia (APL) t(15;17)(q22;q12-21). The major interest lies in the chronology of the two diseases: the APL demonstrated an unusual smoldering evolution, suggesting that pre-existing sarcoidosis may have a non-fortuitous immunological impact on leukemic clone proliferation.     

Complete remission in acute promyelocytic leukemia despite the persistence of the 15;17 translocation

Acute promyelocytic leukemia (APL) is a morphologically distinct subtype of acute non-lymphocytic leukemia (ANLL) characterized cytogenetically by the presence of a translocation between chromosomes 15 and 17 (t(15;17]. In contrast to other subtypes of ANLL, morphologic examination of the bone marrow in the early postinduction period fails to identify patients adequately who have a high likelihood of entering remission. Remission has frequently been achieved in APL despite the failure to attain marrow aplasia or eliminate dysplastic progranulocytes after initial induction chemotherapy. In a patient with APL who failed to achieve cytoreduction after a single course of induction chemotherapy, serial cytogenetic studies demonstrated persistence of metaphases with the t(15;17) up to 23 days after induction. However, complete morphologic and cytogenetic remission was subsequently attained by day 29 without further therapy. In APL remission may occur even when induction therapy fails to achieve marrow aplasia or to eradicate replicative cells with abnormal karyotype promptly. In order to avoid excessive exposure to toxic therapy, new strategies may be necessary to identify, early in treatment, patients with APL who will require only one course of induction chemotherapy to enter remission successfully.     

Therapy-related acute promyelocytic leukemia with a t(9;22)(q34;q11) and t(15;17)(q22;q11 to approximately 12) subclone

The translocation (15;17) is a typical marker of acute promyelocytic leukemia, whereas t(9;22) is predominantly associated with chronic myelogenous leukemia, and seldom with acute myelogenous leukemia. Furthermore, the association between t(15;17) and t(9;22) in the same cell is extremely rare. We present a case of therapy-related acute promyelocytic leukemia (t-APL) with a subclone accompanied by karyotype 46, XX, t(9; 22)(q34;q11), t(15 ;17)(q22;11 to approximately 12) at onset. A 75-year-old woman was diagnosed as having non-Hodgkin lymphoma of the thyroid gland in July 1997. She was treated with a CHOP-like regimen, but complete remission (CR) was not achieved. She then underwent surgical resection of her thyroid gland, and was treated with etoposide (total dose 16775 mg) from February 1998 to May 2000. In June 2000, having developed t-APL, she was referred to our department. The patient attained CR following treatment with chemotherapy containing all-trans retinoic acid. Ten months later she relapsed, but lost the t(9;22), while maintaining the t(15;17).