Alternative genetic pathways and cooperating genetic abnormalities in the pathogenesis of therapy-related myelodysplasia and acute myeloid leukemia.

Alternative genetic pathways were previously outlined in the pathogenesis of therapy-related myelodysplasia (t-MDS) and acute myeloid leukemia (t-AML) based on cytogenetic characteristics. Some of the chromosome aberrations, the recurrent balanced translocations or inversions, directly result in chimeric rearrangement of genes for hematopoietic transcription factors (class II mutations) which disturb cellular differentiation. Other genetic abnormalities in t-MDS and t-AML comprise activating point mutations or internal tandem duplications of genes involved in signal transduction as tyrosine kinase receptors or genes more downstream in the RAS-BRAF pathway (class I mutations). The alternative genetic pathways of t-MDS and t-AML can now be further characterized by a different clustering of six individual class I mutations and mutations of AML1 and p53 in the various pathways. In addition, there is a significant association between class I and class II mutations possibly indicating cooperation in leukemogenesis, and between mutations of AML1 and RAS related to subsequent progression from t-MDS to t-AML. Therapy-related and de novo myelodysplasia and acute myeloid leukemia seem to share genetic pathways, and surprisingly gene mutations were in general not more frequent in patients with t-MDS or t-AML as compared to similar cases of de novo MDS and AML studied previously.

Amplification or duplication of chromosome band 21q22 with multiple copies of the AML1 gene and mutation of the TP53 gene in therapy-related MDS and AML.

Amplification or duplication of the AML1 gene at chromosome band 21q22 was detected by FISH using a locus-specific probe in three out of 171 unselected patients with therapy-related myelodysplasia (t-MDS) or t-AML (1.7%). In two patients AML1 signals were located tandemly on derivative chromosomes, in one patient on a dic(9;21) and in the the other patient on a derivative chromosome 18 made up of interchanging layers of material from chromosomes 9, 14, 18, and 21. In the third patient three single supernumerary copies of AML1 were located on derivatives of chromosomes 19 and 21. All three patients were older, had previously received therapy with alkylating agents without topoisomerase II inhibitors, had complex karyotypes including abnormalities of chromosomes 5 or 7, and presented acquired point mutations of the TP53 gene. No point mutations of the AML1 gene were observed. The results support a pivotal role of impaired TP53 function in the development of gene amplification or duplication in t-MDS and t-AML.

Mutations of genes in the receptor tyrosine kinase (RTK)/RAS-BRAF signal transduction pathway in therapy-related myelodysplasia and acute myeloid leukemia.

Mutations of the FLT3, c-KIT, c-FMS, KRAS, NRAS, BRAF and CEBPA genes in the receptor tyrosine kinase (RTK)/RAS-BRAF signal-transduction pathway are frequent in acute myeloid leukemia (AML). We examined 140 patients with therapy-related myelodysplasia or AML (t-MDS/t-AML) for point mutations of these seven genes. In all, 11 FLT3, two c-KIT, seven KRAS, eight NRAS and three BRAF mutations were identified in 29 patients (21%). All but one patient with a FLT3 mutation presented with t-AML (P=0.0002). Furthermore, FLT3 mutations were significantly associated with previous radiotherapy without chemotherapy (P=0.03), and with a normal karyotype (P=0.004), but inversely associated with previous therapy with alkylating agents (P=0.003) and with -7/7q- (P=0.001). RAS mutations were associated with AML1 point mutations (P=0.046) and with progression from t-MDS to t-AML (P=0.008). Noteworthy, all three patients with BRAF mutations presented as t-AML of M5 subtype with t(9;11)(p22;q23) and MLL-rearrangement (P=0.01). In t-AML RAS/BRAF mutations were significantly associated with a very short survival (P=0.017). Half of the patients with a mutation in the RTK/RAS-BRAF signal-transduction pathway (denoted 'class-I' mutations) simultaneously disclosed mutation of a hematopoietic transcription factor (denoted 'class-II' mutations) (P=0.046) suggesting their cooperation in leukemogenesis.

Point mutation of the ras protooncogenes and chromosome aberrations in acute nonlymphocytic leukemia and preleukemia related to therapy with alkylating agents.

Nine cases of overt acute nonlymphocytic leukemia and four cases of preleukemia or a myelodysplastic syndrome, all related to intensive treatment with alkylating agents, were studied cytogenetically and investigated using a rapid and sensitive dot blot screening procedure for point mutations in the Ha-ras, Ki-ras, and N-ras protooncogenes within codons 12, 13, and 61. The technique involves a selective amplification of genomic DNA sequences containing the codon sequence of interest, in combination with oligonucleotide hybridization. Examining fractionated mononuclear cells from bone marrow or peripheral blood, an N-ras mutation at position 13 was observed in one patient with overt leukemia, resulting in a base change from GGT to TGT thus converting glycine to cysteine. The other cases exhibited no ras gene mutations. It is surprising that c-ras mutations are only occasionally observed in overt acute nonlymphocytic leukemia related to treatment with alkylating agents, as such abnormalities have often been observed in acute nonlymphocytic leukemia de novo, and as many alkylating agents are known to produce DNA adducts leading to point mutations and substitution of single amino acids. The fact that deletions of varying parts of the long arms of chromosomes 5 and 7 are observed in most cases of therapy-related acute nonlymphocytic leukemia and preleukemia, as confirmed by our own series of 71 patients, suggests that loss of heterozygosity for specific alleles on the two chromosomes, rather than activation of a protooncogene, could be an important step in leukemogenesis.

Partial tandem duplication of ALL1 as a recurrent molecular defect in acute myeloid leukemia with trisomy 11.

Gains of a single chromosome are frequent cytogenic findings in human cancer, but no molecular rearrangement has been consistently associated with any trisomy. In acute myeloid leukemia (AML), trisomy 11 (+11) occurring as a sole abnormality is the third most common trisomy. We have shown that the ALL1 gene, located at 11q23, can be rearranged as a result of a partial tandem duplication in two such cases of AML. To test the hypothesis that the partial tandem duplication of ALL1 is the recurrent molecular defect in cases of AML presenting with +11 as a sole cytogenic abnormality, we performed Southern analysis and PCR for defects of ALL1 in 17 cases of AML and one case of myelodysplastic syndrome with +11 or +11q but without cytogenic evidence of a structural abnormality involving 11q23. Twelve cases (67%) had rearrangement of ALL1, including 10 of 11 patients (91%) with +11 as a sole abnormality and 2 of 7 cases (29%) with +11 and other aberrations; all were classified as FAB M1 or M2. In 10 of the 12 cases, material was available for additional characterization; a partial tandem duplication of ALL1 was detected in each of these 10 cases (100%). Four cases demonstrated previously unreported duplications, two of which were detectable only by reverse transcription-PCR. Four patients with the ALL1 duplication also displayed a loss of material from 7q, suggesting an association between these two findings. We conclude that the partial tandem duplication of ALL1 is present in most, if not all, cases of AML with +11 as a sole abnormality, and can be found in cases of AML with +11 or +11q accompanied by other cytogenic abnormalities. The duplication is more prevalent in AML than was recognized previously in part because its size and location vary considerably, requiring a variety of molecular probes for detection. Our finding of the ALL1 duplication as a consistent defect in patients with +11 represents the first identification of a specific gene rearrangement associated with recurrent trisomy in human cancer.

Mutations with loss of heterozygosity of p53 are common in therapy-related myelodysplasia and acute myeloid leukemia after exposure to alkylating agents and significantly associated with deletion or loss of 5q, a complex karyotype, and a poor prognosis.

PURPOSE: To study mutations and loss of heterozygosity (LOH) of p53 in therapy-related myelodysplasia (t-MDS) and acute myeloid leukemia (t-AML). PATIENTS AND METHODS: Fifty-two unselected patients with t-MDS and 25 patients with t-AML were studied by polymerase chain reaction (PCR)-single-strand conformational polymorphism (SSCP) at the DNA level and by reverse transcriptase (RT)-PCR-SSCP at the mRNA level, and cases with aberrant SSCP patterns were sequenced. RESULTS: Somatically acquired mutations of p53 were observed in 21 of 77 cases of t-MDS or t-AML, and 19 of these 21 patients had received alkylating agents. Single-base substitutions at A:T pairs were more common in t-MDS and t-AML, whereas single-base substitutions at G:C pairs are most common in MDS and AML de novo and in solid tumors. Six patients demonstrated a cytogenetic loss of 17p13, and these six and an additional nine patients with p53 mutations demonstrated LOH of p53 at the DNA or mRNA level. This suggests a cytogenetic loss of the normal p53 allele in these nine cases combined with duplication of the homologous chromosome 17 carrying the mutated p53 allele. Mutations of p53 were significantly associated with deletion or loss of 5q (P <.0001) and a complex karyotype (P =.0001), but surprisingly were not associated with deletion or loss of 7q (P =.73), and were infrequent in patients with balanced chromosome translocations (P =.03). Mutations of p53 were more common in older patients (P =.036) and were associated with an extremely poor prognosis (P =.014), apparently restricted to the 15 cases with LOH of p53 ( P =.046). CONCLUSION: Mutations with loss of function of p53 are significantly associated with deletion or loss of 5q in t-MDS and t-AML after previous treatment with alkylating agents and are associated with genetic instability.

Inversion of chromosome 16 and uncommon rearrangements of the CBFB and MYH11 genes in therapy-related acute myeloid leukemia: rare events related to DNA-topoisomerase II inhibitors?

PURPOSE: To evaluate the frequency of inversion of chromosome 16 (inv[16]) and the type of rearrangement of the CBFB and MYH11 genes in therapy-related acute myeloid leukemia (t-AML) and to evaluate a possible relationship to specific types of previous chemotherapy. PATIENTS AND METHODS: Cytogenetic studies were performed in 180 consecutive patients with therapy-related myelodysplasia (t-MDS) or t-AML in Copenhagen and in 270 consecutive patients in Chicago. Leukemic cells were available for studies of the molecular biology in 72 patients, including four with inv(16). RESULTS: An inv(16)(p13q22) was observed in only two of 180 cases of t-MDS and t-AML in Copenhagen and in only four of 270 cases of t-MDS and t-AML in Chicago. Four patients with t-AML and inv(16) previously had received combination chemotherapy, which included an alkylating agent, and in two a DNA topoisomerase II inhibitor was included (mitoxantrone and etoposide). One patient had received paclitaxel followed by etoposide and one patient had received radiotherapy only. One patient, previously treated with mitoxantrone and cyclophosphamide for breast cancer, presented a new and, to our knowledge not previously reported, type of fusion transcript, with breakpoint at nt 399 of the CBFB gene and at nt 2134 of the MYH11 gene. Two patients previously treated with alkylating agents both presented the less common type D transcript, whereas the most common A transcript, observed in 80% of acute myeloid leukemia (AML) de novo with inv(16), only was observed in the patient treated with paclitaxel and etoposide for leiomyosarcoma. Bone marrow or blood cells from 68 patients with t-MDS and t-AML without an inv(16) all were found to be negative for chimeric rearrangement between the CBFB gene and the MYH11 gene. CONCLUSION: The present study and a review of the literature shows that inv(16) is an uncommon aberration in t-AML and, like balanced translocations to chromosome bands 11q23 and 21q22 and the t(15;17), often is associated with prior chemotherapy with DNA topoisomerase II inhibitors. Breakpoints within the MYH11 gene may vary between t-AML and AML de novo.

Acute monocytic or myelomonocytic leukemia with balanced chromosome translocations to band 11q23 after therapy with 4-epi-doxorubicin and cisplatin or cyclophosphamide for breast cancer.

PURPOSE: To report five cases of acute monocytic or myelomonocytic leukemia after chemotherapy with 4-epidoxorubicin for breast cancer and to evaluate the risk of leukemia after the use of this drug. PATIENTS AND METHODS: One hundred fifty-seven patients with advanced breast cancer were randomized to either 4-epi-doxorubicin plus cisplatin or 4-epi-doxorubicin alone. An additional 203 patients were treated prospectively with 4-epi-doxorubicin alone. All were observed closely for leukemic complications. RESULTS: Three patients from the randomized study developed leukemia; all were in the subgroup of 74 patients who received 4-epi-doxorubicin plus cisplatin, whereas no leukemia was observed among the remaining 83 patients in the randomized study or among the additional 203 patients who were treated prospectively with 4-epi-doxorubicin alone (P = .023, log-rank test). In the subgroup of 74 patients who were treated with 4-epi-doxorubicin plus cisplatin, the cumulative risk of leukemia was 16.0% +/- 9.9% (mean +/- SE) 33 months after the start of therapy; the relative risk was 668 (95% confidence interval [Cl], 138 to 1,953). Two other cases of acute monocytic and myelomonocytic leukemia were observed after 4-epi-doxorubicin plus alkylating agents were administered for breast cancer. Three of five cases of leukemia presented balanced translocations to chromosome band 11q23 and two, loss of a whole chromosome no. 7 or its long arm. CONCLUSIONS: 4-epi-doxorubicin is leukemogenic, and the leukemias are often acute monocytic or myelomonocytic with balanced chromosome translocations to band 11q23, such as in the leukemias after therapy with the epipodophyllotoxins. Furthermore, our results suggest a synergistic effect in leukemogenesis between 4-epi-doxorubicin targeting DNA-topoisomerase II and directly genotoxic drugs such as cisplatin or alkylating agents.

Internal tandem duplications of the FLT3 and MLL genes are mainly observed in atypical cases of therapy-related acute myeloid leukemia with a normal karyotype and are unrelated to type of previous therapy.

Eighty-two unselected cases of therapy-related myelodysplasia (t-MDS) or acute myeloid leukemia (t-AML) were investigated for internal tandem duplications of the FLT3 gene (FLT3/ITD), for internal tandem duplications of the MLL gene (MLL/ITD) and for mutations of the WT1 gene. FLT3/ITD were observed in three patients, another two patients presented MLL/ITD whereas mutations of the WT1 gene were not observed. All FLT3/ITD included the tyrosine-rich stretch between codons 589 and 599, and both MLL/ITD presented break points within Alu-repeats, as previously observed in de novo AML. The ITD were not related to any specific type of previous therapy, but three out of the five cases were observed among only six patients with overt t-AML and a normal karyotype (P = 0.0043). Interestingly, one of the patients with FLT3/ITD presented overt t-AML of subtype M1 with a normal karyotype after treatment with an alkylating agent. Complete remission was observed following treatment with daunorubicin and cytosine arabinoside, but after 37 months the patient relapsed with t-AML of subtype M3 with a t(15;17) and the same FLT3/ITD was still present. Thus FLT3/ITD may in this case represent a primary event in leukemogenesis, whereas the t(15;17) may represent a secondary event most likely induced by subsequent therapy. In conclusion, FLT3/ITD and MLL/ITD are mainly observed in uncharacteristic cases of t-AML with a normal karyotype and unrelated to previous therapy for which reason they could represent sporadic cases of de novoAML.

Increased frequency of dicentric chromosomes in therapy-related MDS and AML compared to de novo disease is significantly related to previous treatment with alkylating agents and suggests a specific susceptibility to chromosome breakage at the centromere.

Dicentric chromosomes are observed in many malignant diseases including myelodysplasia (MDS) and acute myeloid leukemia (AML) and have often been observed in a subset of these diseases, namely therapy-related MDS (t-MDS) and AML (t-AML). Using fluorescence in situ hybridization (FISH) with centromere-specific probes, we investigated the frequency and type of dicentric chromosomes in 180 consecutive patients with t-MDS and t-AML and in 231 consecutive patients with de novo MDS and AML, whose karyotypes had been studied previously by conventional G-banding. Twenty-seven out of 180 patients with t-MDS or t-AML presented dicentric chromosomes compared to only seven out of 231 patients with de novo disease (P = 0.00003). A dic(1q;7p) was observed in 10 cases, a dic(5p;17q) was observed in six cases, whereas various isodicentric chromosomes were observed in six cases. Excluding these six cases with isodicentrics, all 25 patients with dicentric chromosomes had involvement of at least one of the chromosome arms 1q, 5p, or 7p resulting in monosomy for 5q or 7q, and/or trisomy for 1q. Patients with dicentric chromosomes presented significantly more often as t-MDS compared to patients without dicentrics (P = 0.046), and the presence of a dicentric chromosome was significantly related to previous therapy with alkylating agents (P = 0.026). Thus, only one out of 27 patients with a dicentric chromosome had not previously received an alkylating agent. A specific susceptibility to breakage at the centromere after exposure to alkylating agents is suggested and may explain the frequent loss of whole chromosomes, in particular chromosomes 5 and 7 in t-MDS and t-AML, if the breaks are not followed by rejoining. Leukemia (2000) 14, 105-111.

Methylation of p15INK4B is common, is associated with deletion of genes on chromosome arm 7q and predicts a poor prognosis in therapy-related myelodysplasia and acute myeloid leukemia.

The p14(ARF), p15(INK4B), and p16(INK4A) genes are important negative cell-cycle regulators often inactivated by deletions, mutations, or hypermethylation in malignancy. Hypermethylation of the three genes was studied in 81 patients with therapy-related myelodysplasia (t-MDS) or acute myeloid leukemia (t-AML) by methylation-specific PCR, and p15 methylation additionally by bisulfite genomic sequencing. In all, 55 patients disclosed p15 methylation, five patients showed p16 methylation, whereas p14 methylation was not observed. Methylation of p15 was closely associated with deletion or loss of chromosome arm 7q (P=0.0006). In t-MDS, the p15 methylation frequency and the p15 methylation density both increased significantly by stage (P=0.004 and 0.0002), and p15 methylation frequency increased with an increasing percentage of myeloblasts in the bone marrow (P=0.006). In a two-variable Cox model including the percentage of myeloblasts, p15 methylation was an independent prognostic factor (P=0.005). Methylation of p15 was less common in t-AML of subtype M5 than in other FAB subtypes (P=0.03). Methylation of p15 was unrelated to type of previous therapy, to latent period from start of therapy, to platelet count, and to p53 mutations. Inactivation of p15 and deletion of genes on chromosome arm 7q possibly cooperate in leukemogenesis.

Chemotherapy-related - late occurring - Philadelphia chromosome in AML, ALL and CML. Similar events related to treatment with DNA topoisomerase II inhibitors?

Therapy with DNA topoisomerase II inhibitors has been shown to result in an increased risk of acute myeloid leukemia (AML), often presenting balanced translocations to chromosome bands 11q23 and 21q22. Also other balanced aberrations, more rarely observed in therapy-related AML (t-AML), such as t(15;17) and inv(16) have been associated with these drugs. Recently we observed a case of chronic myeloid leukemia (CML) with t(9;22) after therapy of a germ cell tumor with etoposide, cisplatin and bleomycin. Based on this case and a review of chemotherapy-related leukemias with t(9;22) from the literature, we suggest a causal relationship between therapy with DNA topoisomerase II inhibitors and development of various types of leukemia carrying the Philadelphia chromosome.

High risk of therapy-related leukemia after BEAM chemotherapy and autologous stem cell transplantation for previously treated lymphomas is mainly related to primary chemotherapy and not to the BEAM-transplantation procedure.

A cohort of 76 patients with previous chemotherapy for Hodgkin's disease and non-Hodgkin lymphomas received high-dose carmustine, etoposide, cytosine-arabinoside and melphalan (BEAM) followed by autologous stem cell transplantation (ASCT) and was followed for relapse and development of leukemic complications. Six patients, four with Hodgkin's disease and two with non-Hodgkin lymphomas, developed leukemic complications, myelodysplasia (MDS) in four cases and overt acute myeloid leukemia (AML) in two. All six showed an abnormal karyotype, in four of them highly characteristic of therapy-related MDS (t-MDS) and therapy-related AML (t-AML). The cumulative risk of t-MDS and t-AML increased from 16 months after start of the primary chemotherapy for lymphoma and reached 17.3% (s.e. 8.5%) after 74 months. If calculated from start of BEAM and ASCT, the cumulative risk increased as early as 4 months and reached 24.3% (s.e. 12.9%) after 43 months. For the whole course of the disease, the relative risk (RR) of AML was 357 (95% CI: 43-1290), as two overt leukemias were observed vs 0.0056 expected cases of de novo AML. In the present cohort the risk of t-MDS and t-AML although high, did not differ from our previous experience in patients treated conventionally for Hodgkin's disease and non-Hodgkin lymphomas, and did not differ for patients receiving stem cells isolated from the bone marrow as compared to patients receiving stem cells isolated from peripheral blood. Antecedent chemotherapy seems to be the critical factor for the development of t-MDS and t-AML rather than the BEAM and ASCT regimen, which however may accelerate the evolution of the disease.

Causality of myelodysplasia and acute myeloid leukemia and their genetic abnormalities.

New insights into causative factors for the development of myelodysplasia (MDS) and acute myeloid leukemia (AML), with associations to specific cytogenetic and genetic abnormalities have been obtained primarily from studies of patients with the therapy-related subsets of the two diseases. Current knowledge now makes it possible to distinguish between at least seven major genetic subgroups of MDS and AML, and has directed research towards more specific causative factors also for de novo MDS and AML.

Aclarubicin plus cytosine arabinoside versus daunorubicin plus cytosine arabinoside in previously untreated patients with acute myeloid leukemia: a Danish national phase III trial. The Danish Society of Hematology Study Group on AML, Denmark.

A regimen of aclarubicin (ACR) of 75 mg/m2 daily for 3 days plus a continuous intravenous infusion of cytosine arabinoside (ara-C) of 100 mg/m2 per day for 7 days was compared with daunorubicin (DNR) 45 mg/m2/day for 3 days plus ara-C for 7 days as first-line chemotherapy of de novo acute myeloid leukemia (AML) in a randomized, nationwide Danish study. A total of 180 patients aged between 17 and 65 years were entered onto the protocol. Patients who achieved complete remission (CR) were given five courses of intensive consolidation therapy consisting of two courses of high dose ara-C, two courses of amsacrine plus etoposide, and one course of DNR plus ara-C. Of 174 evaluable patients, 99 achieved CR. The rate of CR was significantly higher on ACR plus ara-C than on DNR plus ara-C [66% versus 50% (p = 0.043)] and decreased significantly with increasing age. The hematological toxicity was identical for the two regimens. A total of 83 patients entered consolidation therapy. At 4 years, 37% of patients with CR following ACR were still in remission compared with 33% following DNR (p = 0.48), and the total survival at 4 years was 29% versus 20% (p = 0.26). The duration of remission and total survival both decreased with increasing age. ACR plus ara-C seem at least as good or better than DNR plus ara-C as first-line chemotherapy of AML.

Therapy-related myelodysplasia and acute myeloid leukemia. Cytogenetic characteristics of 115 consecutive cases and risk in seven cohorts of patients treated intensively for malignant diseases in the Copenhagen series.

Therapy-related acute myeloid leukemia (t-AML), often presenting as myelodysplasia (t-MDS), has become the most serious long-term complication of cancer therapy and offers a unique opportunity to study chemical leukemogenesis. Seven cohorts of patients treated for six different types of primary tumor have been followed closely for leukemic complications, and 115 consecutive patients with t-MDS or t-AML, including 45 cases from the cohorts, have been investigated cytogenetically at our institutions during the past 16 years. In patients primarily treated with alkylating agents, the risk of t-MDS and t-AML increased by approximately 1% per year from 2 to at least 8 years after start of treatment. In most cases, the disease presented as t-MDS with loss of a whole chromosome 5 or 7, or various parts of their long arms, and the leukemias were of FAB-subtypes M1, M2, or M4. In patients treated with drugs targeting at DNA-topoisomerase II, such as etoposide, doxorubicin, 4-epidoxorubicin, or mitoxantrone combined with drugs reacting directly with DNA, such as cisplatin or alkylating agents, the risk of leukemia increased much more steeply from only one year after start of therapy. These early onset cases often presented as overt leukemia of FAB-subtypes M4 or M5 with balanced translocations to chromosome bands 11q23 and 21q22, whereas later onset cases often shared characteristics with cases observed after therapy with alkylating agents alone. Both alkylation of DNA and poisoning of DNA-topoisomerase II may result in development of t-AML with different clinical and cytogenetic characteristics. There may be a synergistic leukemogenic effect between the two types of drug, and in patients with germ cell tumors treated with etoposide, cisplatin and bleomycin, reassessment suggested the risk of leukemia to increase exponentially with increasing doses of cisplatin and etoposide.

Long-term survival and development of secondary malignancies in patients with acute myeloid leukemia treated with aclarubicin or daunorubicin plus cytosine arabinoside followed by intensive consolidation chemotherapy in a Danish national phase III trial. Danish Society of Haematology Study Group on AML.

In 1991 we reported the results from a prospective randomised phase 3 trial comparing 7 days continuous infusion of cytosine arabinoside (ara-C) combined with either daunorubicin (DNR) or aclarubicin (ACR) as direct i.v. injection for 3 days as induction chemotherapy (CT) for patients with de novo acute myeloid leukemia (AML) followed by early intensive consolidation CT with two alternating cycles of high-dose ara-C and two cycles of amsacrine plus etoposide, and finally 3 days of daunomycin plus 7 days of ara-C as administered for induction of remission. A total of 174 patients with de novo AML in the age group 17-65 years were included. The patients have now been followed till death or for at least 7 years, and an evaluation of the long-term survival and the risk of developing secondary neoplasms has been made. The overall survival rate 5-years after diagnosis was 23%, and after 10 years 19%. No difference was found between the two treatment regimens in overall survival or disease-free survival (DFS). For the subgroup of 99 patients who achieved complete remission after one or two induction courses, 5- and 10-year survival rates were 35% and 31% respectively, with the highest survival rates in the age group 17-39 years (57% at 5 years) as compared with 27% in patients aged 40-60 years (P= 0.007). Seven secondary neoplasms were diagnosed simultaneously with or after the diagnosis of AML indicating a standardized incidence ratio (SIR) of 3.41, (95% CI: 1.60-7.26). In three cases the secondary neoplasms were diagnosed simultaneously with the AML diagnosis and were for that reason completely unrelated to the chemotherapy administered for AML, as the psammomatous meningeoma diagnosed after only 8 months. The remaining three neoplasms which developed subsequently did not significantly exceed the expected number, with a SIR = 1.46 (0.47-4.57). Thus, no increased risk of solid tumors causally related to the intensive chemotherapy for de novo AML was observed. However, a generally increased risk of solid tumors in patients diagnosed simultaneously with the AML diagnosis seems likely. Over 20% of the patients were alive and in complete remission 5 years after the AML diagnosis, and they have a high probability of surviving the next 5-year period.

Radiotherapy- and chemotherapy-induced myelodysplasia and acute myeloid leukemia. A review.

A highly increased risk of myelodysplasia (MDS) and acute myeloid leukemia (AML) has been demonstrated following therapy with alkylating agents. The risk increases with cumulative dose and with the age of the patient. Most cases of MDS and AML following therapy with alkylating agents present chromosome aberrations, primarily loss of whole chromosomes No. 5 and/or No. 7 or various parts of the long arms of these chromosomes. The risk of MDS and AML following high-voltage radiotherapy is much lower. Recently an increased risk of AML has been demonstrated following therapy with the epipodophyllotoxins etoposide and teniposide. These leukemias typically present without preceding MDS and often show balanced aberrations of chromosome bands 11q23 and 21q22.

Chromosome characteristics of therapy-related acute non-lymphocytic leukemia and preleukemia: possible implications for pathogenesis of the disease.

Most cases of therapy-related acute nonlymphocytic leukemia or preleukemia show chromosome aberrations, primarily loss of whole chromosomes No. 5 and/or No. 7 or the long arms of these two chromosomes. Other abnormalities involve chromosome No. 21, often rearranged at band 21q22, and chromosome No. 17, in some cases rearranged at band 17p13. Important cellular genes have recently been localized to these regions, including the gene for one hematopoietic growth factor and the gene for the receptor for another hematopoietic growth factor. It is suggested that the total loss or change of structure or expression of some of these genes resulting from the various chromosome aberrations may be of pathogenetic significance in therapy-related acute nonlymphocytic leukemia.

The prognostic significance of chromosomal analysis and immunophenotyping in 117 patients with de novo acute myeloid leukemia.

Chromosomal abnormalities is one of the most important prognostic factors in acute myeloid leukemia (AML). Other parameters which may influence the prognosis include age, French-American-British-type, clinical variables and possibly the expression of certain immunophenotypic surface makers. However, only rarely has the expression of these markers been analyzed in multivariate models including the information from cytogenetics and clinical variables. We conducted a retrospective study of 117 consecutive adult patients with de novo AML diagnosed and treated in our institution during a 6-year period. Following standard induction chemotherapy with daunomycin and cytosine arabinoside 75 patients (64%) achieved complete remission (CR). The overall 5 year survival rate was 23% and, for patients achieving CR, 30%. When all patients were analyzed age, chromosomal aberration and lack of CD33 expression were of independent prognostic value. The overall 5 year survival rate was 28% for patients aged 55 years or younger, 25% for patients aged 56-65 years and 4% for those > 65 years, P = 0.041. Patients with good-risk chromosomal abnormalities presented an overall 5 year survival of 36%, compared to 25% in patients with normal karyotype, 22% in patients with intermediate risk abnormalities and 5% in patients with poor-risk abnormalities, P = 0.004. Patients with CD33+ myeloblasts had an overall survival of 25% at 5 years compared to 0% in the CD33- patients, P = 0.021. Analysis of the expression of CD7, CD34 and terminal deoxynucleotidyl transferase on myeloblasts had no impact on overall survival in a multivariate analysis. Thus, this study confirmed the prognostic value of age and cytogenetic risk group and defined CD33 as a novel factor of independent prognostic importance in adult de novo AML.