Spontaneous regression of a solitary cerebral metastases in renal carcinoma followed by meningioma development under medroxyprogesterone acetate therapy

A case of regression of a probable cerebral metastasis of a hypernephroma after nephrectomy and hormone therapy is presented. The patient subsequently developed a meningioma after therapy with medroxyprogesterone acetate. A relationship between meningioma growth and sex hormones has been documented, but little is known about the effect of hormone therapies on tumour growth.

Acute leukaemia and other secondary neoplasms in patients treated with conventional chemotherapy for multiple myeloma: a Finnish Leukaemia Group study

The occurrence of acute leukaemia and other secondary neoplasms in 432 patients treated with conventional chemotherapy for multiple myeloma was analysed after a follow-up period of 11-19 yr (mean 16 yr). The number and organ-specific distribution of observed solid neoplasms was close to that expected in the general population. Non-Hodgkin's lymphoma developed in three patients (expected 0.7, p = 0.19). Acute leukaemia was diagnosed in 14 patients with an actuarial risk of 9.8% at 9 yr. No further cases were diagnosed thereafter. The average numbers of courses (26.2 vs. 25.5) and cumulative doses of melphalan (1440 and 1400 mg) were similar in patients with or without acute leukaemia. It seems possible that the advanced stage of multiple myeloma is more vulnerable to the leukaemogenic effect of melphalan compared with the earlier stages.

Hematologic abnormalities and acute myeloid leukemia in children and adolescents administered intensified chemotherapy for the Ewing sarcoma family of tumors

PURPOSE

Current treatment of the Ewing sarcoma family of tumors (ESFT) includes intensive multiagent chemotherapy with topoisomerase II inhibitors, alkylating agents, and granulocyte colony-stimulating factor (G-CSF). This treatment approach has been associated with myelodysplasia and acute myeloid leukemia. Because macrocytosis and thrombocytopenia are distinctive features of myelodysplasia, the authors evaluated a cohort of patients treated for ESFT to determine the degree and duration of macrocytosis and thrombocytopenia and their relation with the development of therapy-related hematologic malignancies.

PATIENTS AND METHODS

The study group consisted of 73 patients with ESFT treated on two consecutive protocols (EW92 and EW87). Both chemotherapy regimens incorporated the same agents but differed in cumulative drug dose, dose per course, and the use of G-CSF. Platelet counts and the mean corpuscular volume (MCV) of erythrocytes were determined at diagnosis and during follow-up visits after completion of treatment.

RESULTS

Patients in the EW92 group had significantly greater MCVs after treatment than did the less intensively treated EW87 group. These changes persisted throughout the 40-month observation period. Patients in the EW92 group also had lesser mean platelet counts after treatment than those in the EW87 group. MCV differences (from baseline) were inversely related to platelet counts. The cumulative incidence of treatment-related acute myeloid leukemia was 7.8%+/-4.7% at 4 years in the EW92 group and zero in the EW87 group.

CONCLUSION

Patients treated for ESFT with intensive chemotherapy that includes large doses of alkylators, topoisomerase II inhibitors, and G-CSF characteristically have persistently elevated MCVs and decreased platelet counts after completion of therapy. These hematologic abnormalities may represent stem cell damage, predisposing patients to myelodysplasia and acute myeloid leukemia, but further study is needed to establish this relation.

Secondary myelodysplastic syndrome/acute myeloid leukaemia following mitoxantrone-based therapy for breast carcinoma

Of 1774 patients with breast cancer given mitoxantrone (MTZ) with methotrexate (n = 492) or with methotrexate and mitomycin C (n = 1282), nine developed MDS/AML after a median of 2.5 years. Median duration of survival from diagnosis of MDS/AML was 10 months and six patients died. The crude incidence of developing MDS/AML after MMM or MM chemotherapy was 15 per 100,000 patient years follow-up, while the actuarial risk was 1.1% and 1.6% at 5 and 10 years respectively. MTZ-based regimens carry a 10 x higher risk of subsequent MDS/AML compared to that seen in the general population.

Morphological and cytogenetic changes in therapy-related leukemia developed in a t(8;21)-acute myeloid leukemia (M2) patient: sequential cytogenetic and molecular analyses

A patient with acute myeloid leukemia (AML)-M2 with t(8;21)(q22;q22) achieved complete remission with remission-induction chemotherapy followed by consolidation and intensification chemotherapies. T(8;21)(q22;q22) disappeared, but chimeric AML1/MTG8 was continuously detected in bone marrow cells. Following the development of therapy-related leukemia after 1 year, evolution of therapy-related AML-M4 with t(11;17)(q23;q25) and the rearrangement of the MLL gene were observed, while AML/MTG8 disappeared. After reinduction and following intermittent chemotherapies, a subsequent alternative transformation to AML-M2 occurred after detection of t(3;21)(q21;q22), with a break in the AML1 gene shown by interphase fluorescence in situ hybridization analysis. This leukemia transformed to AML-M4 after t(9;22)(q34;q11), with a minor BCR/ABL rearrangement, and then finally to AML-M2. This therapy-related leukemia was resistant to chemotherapy. These findings indicate that alterations in cytogenetic and molecular events caused by chemotherapeutic agents contribute to the sequential evolution of new leukemic clones with different morphology.

Therapy-related acute myeloid leukemia and myelodysplasia after high-dose chemotherapy and autologous stem cell transplantation

Therapy-related myelodysplasia (t-MDS) and acute myeloid leukemia (t-AML) after high-dose chemotherapy (HD-CT) and autologous stem cell transplantation (ASCT) for malignant diseases have become an important problem. The actuarial risk has varied, but has often been high if compared to the risk after conventional therapy. Prior chemotherapy with large cumulative doses of alkylating agents is the most important risk factor. In addition, patient age and previous radiotherapy, particularly the use of total body irradiation (TBI) in the preparative regimen for ASCT, have been identified as risk factors. In 3 studies, patients transplanted with CD34(+ )cells from peripheral blood after chemotherapy priming showed a higher risk of t-MDS or t-AML than patients transplanted with cells isolated from the bone marrow without priming. To what extent this higher risk relates to the prior therapy with a different contamination with preleukemic, hematopoietic precursors of the CD34(+) cells obtained by the 2 methods, or is a direct result of chemotherapy priming, or of an increasing awareness of these complications, remains to be determined. The latent period from ASCT to t-MDS and t-AML has often been short, 12 months or less in 27% of the patients. Bone marrow pathology of early cases of t-MDS after ASCT has often been neither diagnostic nor prognostic, but most patients presented chromosome aberrations, primarily deletions or loss of the long arms of chromosomes 5 and 7. The prognosis was in general poor, although 17% with indolent t-MDS survived more than 18 months from diagnosis, and most of these presented a normal karyotype or a single chromosome aberration.

Undifferentiated leukemia following treatment of gastric cancer with 5 fluorouracil, doxorubicin, mitomycin C chemotherapy

Secondary leukemias are an increasingly well recognized complication of cancer chemotherapy. We report on the development of undifferentiated leukemia in a forty one year lady, eighteen months after treatment of gastric cancer with 5-fluorouracil (5 FU), doxorubicin and mitomycin C. She developed progressive weakness and pancytopenia over a period of few months. Leukemic blasts which were undifferentiated by immunophenotyping were seen in her peripheral blood. She died of intracranial haemorrhage during induction chemotherapy for the leukemia. Undifferentiated leukemia is a rare complication of FAM chemotherapy for gastric cancer.

Increase therapy-related leukemia secondary to breast cancer

Therapy-related leukemia associated with chemotherapy, particularly alkylating agents and topoisomerase II inhibitors, are being reported with increasing frequency in the literature mainly after breast cancer. We also observed an increasing number of such leukemias in the data base of the specialized registry of hematological malignancies of the Côte d'Or department. Between 1980 and 1998, 156 AML and RAEB-t were registered in women in Côte d'Or. Among them, 12 occurred in women with breast cancer history (7.7%). Analysis by period of time shows a significant increase in the proportion of therapy-related leukemia secondary to breast cancer (P < 0.02). Chemotherapy including topoisomerase II inhibitors was used in 10 cases in which mitoxantrone was used in eight cases. In these eight cases, leukemia had clinical and biological characteristics usually described with topoisomerase II inhibitors but 44% were promyelocytic sub-type with the t(15;17) specific karyotypic abnormality. These data on a well-defined population demonstrate the increased proportion of therapy-related leukemia secondary to breast cancer, probably due to the use of mitoxantrone.

Chemotherapy of secondary leukemias

Chemotherapy of secondary leukemias is currently still considered to be associated with poor results. However, recent data suggest that the response to remission induction may substantially differ according to the previous medical history of the patients. Therapy related leukemia, arising following exposure to previous alkylating agents or radiotherapy, is often associated with chromosomal abnormalities involving chromosomes 5 and 7 and has a particularly bad response, whereas AML after exposure to epipodophyllotoxins or topoisomerase-II active agents could have a somewhat better response. Acute promyelocytic leukemia secondary to treatment of a primary malignant neoplasm seems to be associated with a better response if compared to other cytotypes of AML or to AML arising after transformation of myelodysplasia. However, here the literature data are not in full agreement, as different kinds of approaches have been applied. In fact, even if the problems encountered in treating patients with secondary leukemia are similar to those seen in patients with AML arising in a background of myelodysplasia (resistant disease and prolonged cytopenia after treatment), there are data suggesting that the use of high dose ara-C, with or without fludarabine, can circumvent resistance in a small but significant number of cases. One of the unsolved problems which still remains is how to consolidate the CR induced with high dose ara-C or with cycles based on anthracycline derivatives. In addition, another question relates to the categories of patients in whom chemotherapy may change the expected survival. Intensive post-remission chemotherapy, with or without autologous HSCT, may constitute an appropriate alternative for patients lacking a suitable sibling donor or for older patients who are in remission after chemotherapy and also able to tolerate other cycles of intensive chemotherapy. In this respect, the specific cytogenetic abnormality involved should be considered the most important prognostic factor for response and disease free survival; patients with abnormalities of chromosome 5 and 7 have a particularly low possibility of response and duration of CR. Furthermore, it is still debatable whether patients, especially the elderly, with these characteristics should go through a series of conventional treatments or just receive supportive treatment. On the other hand, patients with better prognostic factors should be entitled to further intensive treatments, taking into account possible delayed recovery and/or possible less successful collection of peripheral or marrow stem cells.

Long-term tamoxifen treatment: a possible aetiological factor in the development of uterine carcinosarcoma: two case-reports and review of the literature

Two cases of uterine carcinosarcoma developing after long-term tamoxifen (TAM) treatment are presented. The patients, 67 and 72 years old, were treated with TAM for 6 and 7 years, continuously. They both developed an heterologous malignant mixed Mullerian tumor (mmMt). At laparotomy, an advanced stage of disease was found with peritoneal spread. In spite of the surgical and the postoperative treatment, they both died of disease, 3 and 10 months later. There are only 10, well documented, similar cases reported. Another 7 were identified in series of uterine malignancies developing after TAM treatment. Considerable evidence suggests that mmMt represents an epithelial cancer with sarcomatous dedifferentiation. Prolonged (> 5 years) TAM treatment may represent a causative factor in the development of this highly lethal disease (80% of the reported patients had a dismal prognosis). Large uterine polyps with special histological features, may represent an intermediate step in the tumor formation. Close follow-up of the patients is warranted.

Leukemia and myelodysplasia effect of multiple cytotoxic therapy in essential thrombocythemia

Essential thrombocythemia (ET) is a chronic myeloproliferative disorder characterized by increased risk of thrombosis and/or hemorrhages. Cytotoxic drugs are mostly used in patients at high risk for thrombotic complications, while their use is still debated in low risk patients because of the risk of leukemia or secondary neoplasm. We discuss the leukemic risk of available treatment strategies in a large cohort of patients. Over a 12 years period we treated 23 patients with busulfan (BU), 1 with pipobroman (Pi), 6 with 32P, 48 with hydroxyurea (HU) in 62 cases associated with acetyl salicylic acid (ASA) while 77 patients received ASA alone and 33 did not receive any therapy. We observed 2 cases of acute leukemia (AL) and 1 of myelodysplastic syndrome (MDS). One of these patients had been treated with 32P and Pi these after with and the other two with BU and HU. They represented 23% of all patients treated with more than 1 cytotoxic agent, 16.6% of 32P treated subjects, 4% of those with HU and 6.4% of those with BU. The case of MDS occurred in a 81 years old female and represents 4% of cases of ET over the 70 years of age. No cases of AL or MDS were observed in patients not receiving cytotoxic therapy (with or without ASA). According to our experience the use of more than one cytotoxic agent in ET confirms the increase in the risk of leukemia in these cases. However, none of the patients treated with HU alone, even for more than 10 years (12 cases) developed AL. No treatment or therapy with ASA alone may be the best choice in young patients with ET with a low risk of thrombotic complications.

Melanoma and additional primary cancers

The aim of this study was to examine the occurrence of additional, unrelated primary cancers in patients with melanoma. Data from the hospital-based, melanoma registry of a specialist unit (the Melanoma Unit at Charing Cross Hospital, London, UK) were compared with the incidence rates in a population-based cancer registry (the Thames Cancer Registry). In total, 2076 patients with the histological diagnosis of melanoma established between 1960 and 1997 who were registered with the Melanoma Unit at Charing Cross Hospital, were included in the study. Patterns in time and in the tumour type of the additional cancers were analysed in the cohort. The relative risk of subsequent cancers was evaluated, the number of expected cancers being calculated by applying incidence rates in the population of south-east England to the person-years of follow-up in the cohort. Sixty-six (3%) of the 2076 evaluable patients had a history of, or developed, 69 histologically verified additional cancers, the commonest being colorectal, breast and lymphoma. Twenty-six additional cancers preceded the diagnosis of melanoma by 1-42 years, 16 were diagnosed within 12 months and 27 followed the diagnosis of melanoma, 1-28 years later. Seven cancers occurred after chemotherapy for metastatic melanoma: two colorectal, one bladder, one renal, two myelodysplasias and one acute myeloid leukaemia. The relative risk of additional cancers developing after the diagnosis of melanoma during the 8537 evaluable years-at-risk was 0.64 (95% confidence interval 0.41-0.96; P = 0.0006). Thus, the risk of additional cancers following treatment for metastatic melanoma in this cohort is small. The potential influence of other factors on the occurrence of additional cancers observed overall in this study requires further investigation.

Secondary leukemia in a child with neuroblastoma while on oral etoposide: what is the cause?

To date little has been reported about the risk of therapy-related leukaemia (t-AML) in children receiving oral etoposide therapy. The authors present a case of t-AML that developed in a child with metastatic neuroblastoma 18 months after he received oral etoposide, given for palliation purpose. The leukemic blasts were examined by morphological, immunohistochemical, cytogenetic, and molecular genetic analyses. Although the t-AML developed following oral etoposide therapy, the child had previously received high-dose, multiagent chemotherapy, and rearrangement of the MLL gene was not demonstrated. The use of modern multiagent therapy often makes it difficult to appropriately apportion blame for causation of specific side effects. Moreover, the etiology of t-AML and mechanism of leukemogenesis are likely to be multifactorial and complex. Further studies on the precise association with different therapies are thus needed. Oral etoposide remains an effective palliative agent and its usage should not be excluded without most careful consideration of the risks.

Genetic polymorphism of thiopurine methyltransferase and its clinical relevance for childhood acute lymphoblastic leukemia

Thiopurine methyltransferase (TPMT) catalyses the S-methylation of thiopurines, including 6-mercaptopurine and 6-thioguanine. TPMT activity exhibits genetic polymorphism, with about 1/300 inheriting TPMT deficiency as an autosomal recessive trait. If treated with standard doses of thiopurines, TPMTdeficient patients accumulate excessive thioguanine nucleotides in hematopoietic tissues, leading to severe hematological toxicity that can be fatal. However, TPMT-deficient patients can be successfully treated with a 10- to 15-fold lower dosage of these medications. The molecular basis for altered TPMT activity has been defined, with rapid and inexpensive assays available for the three signature mutations which account for the majority of mutant alleles. TPMT genotype correlates well with in vivo enzyme activity within erythrocytes and leukemic blast cells and is clearly associated with risk of toxicity. The impact of 6-mercaptopurine dose intensity is also being clarified as an important determinate of event-free survival in childhood leukemia. In addition, there are emerging data that TPMT genotype may influence the risk of secondary malignancies, including brain tumors and acute myelogenous leukemia. Ongoing studies aim to clarify the influence of TPMT on thiopurine efficacy, acute toxicity, and risk for delayed toxicity. Together, these advances hold the promise of improving the safety and efficacy of thiopurine therapy.

Endometrial mesodermal mixed tumor occurring after tamoxifen treatment: report on a new case and review of the literature

BACKGROUND

Anti oestrogenic treatment is widely used for breast cancer treatment and prevention of recurrence. Because of concomitant estrogenic effects, tamoxifen exerts carcinogenic properties on the endometrium. Although secondary endometrial cancers usually present as pure adenocarcinomas, other types of rare tumors have also been reported.

PATIENTS AND METHODS

Herein we describe the clinical, pathological as well as therapeutic aspects of a new case of endometrial mesodermal mixed tumor occurring after long-term tamoxifen therapy.

RESULTS

The present case occured five years after cessation of a five years tamoxifen treatment. The patient failed to respond to doxorubicin and cyclophosphamide when combined to 5-fluorouracil (5-FU), but she reached complete response when the same two drugs were used with carboplatin, suggesting the potential usefullness of platinum derivatives.

CONCLUSIONS

A longer latency period might be observed for endometrial mesodermal mixed tumors as compared to adenocarcinomas and could justify a prolonged clinical and ultrasonographic follow-up of patients during and after tamoxifen treatment. When indicated, chemotherapy might require the use of platinum derivatives in this particular type of secondary tumor.

Predictors of therapy-related leukemia and myelodysplasia following autologous transplantation for lymphoma: an assessment of risk factors

We analyzed data on 612 patients who had undergone high-dose chemoradiotherapy (HDT) with autologous stem cell rescue for Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) at the City of Hope National Medical Center, to evaluate the incidence of therapy-related myelodysplasia (t-MDS) or therapy-related acute myeloid leukemia (t-AML) and associated risk factors. A retrospective cohort and a nested case-control study design were used to evaluate the role of pretransplant therapeutic exposures and transplant conditioning regimens. Twenty-two patients developed morphologic evidence of t-MDS/t-AML. The estimated cumulative probability of developing morphologic t-MDS/t-AML was 8.6% +/- 2.1% at 6 years. Multivariate analysis of the entire cohort revealed stem cell priming with VP-16 (RR = 7.7, P = 0.002) to be independently associated with an increased risk of t-MDS/t-AML. The influence of pretransplant therapy on subsequent t-MDS/t-AML risk was determined by a case-control study. Multivariate analysis revealed an association between pretransplant radiation and the risk of t-MDS/t-AML, but failed to reveal any association with pretransplant chemotherapy or conditioning regimens. However, patients who had been primed with VP-16 for stem cell mobilization were at a 12. 3-fold increased risk of developing t-AML with 11q23/21q22 abnormalities (P = 0.006). Patients undergoing HDT with stem cell rescue are at an increased risk of t-MDS/t-AML, especially those receiving priming with VP-16 for peripheral stem cell collection. (Blood. 2000;95:1588-1593)

Uterine adenocarcinoma after GnRH agonist treatment

We report endometrial adenocarcinoma in two patients shortly after suspending GnRH-agonist treatment for menometrorrhagia and uterine fibromata.

Glutathione S-transferase genotypes in children who develop treatment-related acute myeloid malignancies

Epipodophyllotoxin-associated secondary myeloid leukemia is a devastating complication of acute lymphoblastic leukemia (ALL) therapy. The risk factors for treatment-related myeloid leukemia remain incompletely defined. Genetic deficiencies in glutathione S-transferase (GST) activities have been linked to higher frequencies of a number of human malignancies. Our objective was to determine whether the null genotype for GSTM1, GSTT1, or both, was more frequent in children with ALL who developed treatment-related myeloid malignancies as compared to those who did not. A PCR technique was used to assay for the null genotype for GSTM1 and GSTT1 in 302 children with ALL, 57 of whom also subsequently developed treatment-related acute myeloid leukemia or myelodysplastic syndrome. Among children with ALL who did not develop treatment-related myeloid malignancies, the frequencies of GSTM1 and GSTT1 wild-type, GSTM1 null-GSTT1 wild-type, GSTM1 wild-type-GSTT1 null, and GSTM1 and GSTT1 null genotypes were 40%, 42%, 9% and 9%, respectively. The corresponding frequencies for patients who developed acute myeloid malignancies were 42%, 32%, 11% and 16%, respectively (P = 0.26). A statistically significant increase in the frequency of the GST null genotype was observed in male patients who developed myeloid malignancies as compared to male ALL control patients (P = 0.036), but was not observed in female patients (P = 0.51). Moreover, a logistic regression analysis of possible predictors for myeloid malignancies, controlling for gender and race, did not reveal an association of GSTM1 or GSTT1 null genotypes (P = 0.62 and 0.11, respectively) with treatment-related malignancies. Our data suggest that GSTM1 and GSTT1 null genotypes may not predispose to epipodophyllotoxin-associated myeloid malignancies.

Therapy-related leukemia and myelodysplastic syndrome: a large-scale Japanese study of clinical and cytogenetic features as well as prognostic factors

It is known that alkylating agents and topoisomerase II inhibitors can cause distinct forms of therapy-related leukemia and myelodysplastic syndrome (TRL/MDS). Although several reports have been made on each of these agents separately, no study has yet been conducted to evaluate the effect of these two types of agents in the same population. In a nationwide, large-scale population study, the clinical and cytogenetic features as well as the prognostic factors in 256 patients with TRL/MDS were assessed. Median age was 61 years, and the median period of latency from primary malignancies was 47.9 months. The latency period was significantly shorter in patients undergoing chemotherapy, especially that of topoisomerase II inhibitors, for primary cancer. The morphological diagnosis of TRL/MDS was acute myeloid leukemia in 59% and MDS in 41% of patients. Chromosome abnormalities that frequently involved chromosomes 5, 7 or 11 were documented in 77% of the 189 patients examined. MLL gene rearrangements were detected in 11 of 58 subjects and were correlated with a borderline significance (P = 0.072) with topoisomerase II inhibitor administration. Overall median survival was only 9.7 months. Survival was similar in cases with or without MLL gene rearrangement. Multivariate analysis identified chromosome 5 abnormalities, hypoproteinemia, poor therapy outcomes for primary cancer, C-reactive protein, and thrombocytopenia as being significantly poor prognostic factors (P < 0.05). This large-population study provided a comprehensive update of TRL/MDS status in Japan, identified significant prognostic factors, and enabled the clinical significance of MLL gene rearrangement to be assessed.

Novel SH3 protein encoded by the AF3p21 gene is fused to the mixed lineage leukemia protein in a therapy-related leukemia with t(3;11) (p21;q23)

The mixed lineage leukemia (MLL) gene located at chromosome band 11q23 is frequently rearranged in patients with therapy-related acute monocytic leukemia who received topoisomerase II inhibitors. We have identified a novel fusion partner of MLL (FAB M5b) in a patient who developed t-AML 9 years after treatment for acute lymphoblastic leukemia (ALL). The leukemic cells had a sole karyotypic abnormality of t(3;11) (p21;q23). Screening of a genomic DNA library, prepared from leukemic cell DNA, identified rearranged clones composed of MLL and a novel gene on chromosome 3p21 (AF3p21). The AF3p21 gene encodes a protein of 722 amino acids, which contains an Src homology 3 (SH3) domain, a proline-rich domain, and a bipartite nuclear localizing signal (NLS). RNA analysis demonstrated that exon 6 of the MLL gene fused to exon 2 of the AF3p21 gene. The resulting chimeric protein consists of AT-hooks, methyltransferase, and transcription repressor domains of MLL in addition to the AF3p21 proline-rich domain and NLS but not the AF3p21 SH3 domain.

Translocation (1;11)(q23;p15), a novel simple variant of translocation (7;11)(p15;p15), in a patient with AML (M2) accompanied by non-Hodgkin lymphoma and gastric cancer

We describe a case of an acute myelogenous leukemia (AML) associated with t(1;11) (q23;p15), which is a novel simple variant translocation of t(7;11)(p15;p15). The patient was a Japanese man who had a history of non-Hodgkin lymphoma (NHL) and received MACOP-B combination chemotherapy. Fifteen months after the completion of the treatment, the patient developed AML (M2), which was regarded as a therapy-related leukemia. Cytogenetic study of bone marrow cells showed t(1;11). Although he achieved complete remission by combination chemotherapy, a relapse of NHL and gastric cancer were revealed in the course of the consolidation chemotherapy for AML. The NHL was considered a histological conversion from follicular lymphoma because lymphoma cells carried t(14;18) (q32;q21) and were strongly positive for BCL2 protein. Translocation (1;11), together with AML having t(7;11) or inv(11) involving 11p15, shows that 11p15 is a common acceptor site of these chromosome aberrations and suggests the significance of the NUP98 gene located in 11p15 in therapy-related leukemia.