R. Ludwig

PURPOSE: To determine the optimal duration of preoperative chemotherapy to further increase the proportion of stage I tumors by comparison of two regimens in the treatment of patients older than 6 months who have unilateral Wilms' tumor. PATIENTS AND METHODS: Eligible patients (n = 382) initially received four weekly doses of vincristine (VCR) and two courses of actinomycin D (AMD) and were randomized either to be operated on (4-week group [n = 193]) or to receive 4 more weeks of the same chemotherapy regimen (8-week group [n = 189]). The assessment criterion was the observed percentage of stage I tumors. After surgery, patients were assigned according to tumor stage and histology to four different treatment groups: stage I and favorable histology (n = 5) were to have no further treatment (NFT); stage I and standard histology or anaplasia (n = 244), VCR and AMD for 17 weeks (AV); stages II and III and favorable or standard histology, VCR, AMD, and an anthracycline for 27 weeks (AVE) with no abdominal radiotherapy for stage II N0 disease (n = 75) or with a 15-Gy dose of abdominal irradiation (RTH) in case of stages IIN1 and III (n = 56). Anaplastic tumors staged higher than I or clear-cell sarcoma of the kidney (14), AMD, VCR, an anthracycline, and ifosfamide for 36 weeks (DEVI). RESULTS: No advantage was found in favor of prolonged preoperative treatment. The percentages obtained for the 4-week and the 8-week groups, respectively, were as follows: stage I, 64% versus 62%; intraoperative tumor rupture rate, 1% versus 3%; 2-year EFS, 84% versus 83%; and 5-year OS, 92% versus 87%. Two-year EFS and 5-year OS rates, respectively, of the different treatment groups were as follows: NFT, 100% for both EFS and OS; AV, 88% and 93%; AVE, 84% and 88%; AVE RTH, 71% and 85%; and DEVI, 71% and 71%. The rate of abdominal recurrences in stage II N0 nonirradiated patients was 6.6%. CONCLUSION: The 4-week schedule pre-nephrectomy chemotherapy regimen should be considered the standard treatment. Clinical trials should continue to improve the cure rate of high-risk patients and the quality of life of children with a more favorable prognosis.

In therapy study ALL-BFM 83 a total of 630 patients with acute lymphoblastic leukemia (ALL) have prospectively been evaluated for initial response on therapy with corticosteroids. It was the aim to qualify the in vivo cytoreduction as a new predictor for therapy failure. All patients were exposed for 7 days to prednisone before combination chemotherapy at day 8 has been started. At day 0 one additional dose of Methotrexate was given intrathecally. Therapy for all patients with non-B-ALL has been stratified according to initial tumor burden (risk factor) providing four therapy branches: standard risk low (SR-L), standard risk high (SR-H), medium risk (MR), high risk (HR). After a median duration of study of 21 months, event-free survival (EFS) is for all 630 patients 73%, 81% for SR-L, 76% for SR-H, 69% for MR, and 35% for HR patients (date of evaluation Jan. 1, 1987). In this prospective study, a small subgroup of patients (n = 48; 7.6% of total group) is characterized by greater than 1000 leukemic blasts/mm3 peripheral blood at day 8 after exposure to prednisone. In this subgroup the EFS is only 43% in contrast to 76% in the complementary group of 582 patients with less than 1000 leukemic blasts/mm3 peripheral blood at day 8. Patients of that risk group are derived from therapy branches SR-H, M and HR, the latter contributing relatively most patients. In this negatively selected group all patients with an initial high white blood count, CNS disease at diagnosis, immune subtypes as prae-T-ALL (n = 6), T-ALL (n = 18), null-ALL (n = 5), and males clearly dominate. Of 48 patients with greater than 1000 blasts/mm3 at day 8 4 subsequently failed to enter remission and 8 were qualified as lateresponders. 18 patients relapsed, most of them earlier compared to those of the complementary group. The initial in vivo response on corticosteroid therapy is considered a supplementary prognostic predictor for early failure. It will be utilized in trial ALL/NHL-BFM 86 to qualify patients at the highest risk for relapse. This group of patients is supplemented in addition by non- and lateresponders and children with acute undifferentiated leukemia (AUL). The in vivo corticosteroid test is simple, generates early and reliable results and can be obtained almost always. Thus it may be recommended for use in a multicenter trial.

The WT1 gene, located on chromosome 11p13, is mutated in a low number of Wilms tumors (WTs). Germ-line mutations in the WT1 gene are found in patients with bilateral WT and/or associated genital tract malformations (GU). We have identified 19 hemizygous WT1 gene mutations/deletions in 64 patient samples. The histology of the tumors with mutations was stromal-predominant in 13, triphasic in 3, blastemal-predominant in 1, and unknown in 2 cases. Thirteen of 21 patients with stromal-predominant tumors had WT1 mutations and 10 of these were present in the germ line. Of the patients with germ-line alterations, six had GU and a unilateral tumor, two had a bilateral tumor and normal GU tracts, and two had a unilateral tumor and normal GU. Three mutations were tumor-specific and were found in patients with unilateral tumors without GU. These data demonstrate a correlation of WT1 mutations with stromal-predominant histology, suggesting that a germ-line mutation in WT1 predisposes to the development of tumors with this histology. Twelve mutations are nonsense mutations resulting in truncations at different positions in the WT1 protein and only two are missense mutations. Of the stromal-predominant tumors, 67% showed loss of heterozygosity, and in one tumor a different somatic mutation in addition to the germ-line mutation was identified. These data show that in a large proportion of a histopathologically distinct subset of WTs the classical two-hit inactivation model, with loss of a functional WT1 protein, is the underlying cause of tumor development.

Amplification and enhanced expression of the MYCN oncogene are thought to contribute to the development and progression of human neuroblastomas. Here, we have transfected human neuroblastoma cells that harbor a single MYCN gene copy with the human MYCN gene driven by a viral enhancer/promoter, and we have compared the properties of the parental and the transfected cells. The transfected cells show an enhanced expression of the exogenous MYCN gene. Unlike the parental cells, they have acquired an increased proliferative potential, induce tumors in nude mice, grow in soft agar, and require low amounts of exogenous growth factors in order to proliferate. The MYCN-transfected, but not the parental, cells can synthesize and utilize autocrine growth factor activity. These results demonstrate that enhanced MYCN expression contributes to malignant progression of human neuroblastoma cells, conceivably by stimulating the expression of autocrine growth factor activity.