TP53 mutation profile in chronic lymphocytic leukemia: evidence for a disease specific profile from a comprehensive analysis of 268 mutations.

The TP53 mutation profile in chronic lymphocytic leukemia (CLL) and the correlation of TP53 mutations with allele status or associated molecular genetics are currently unknown. We performed a large mutation analysis of TP53 at four centers and characterized the pattern of TP53 mutations in CLL. We report on 268 mutations in 254 patients with CLL. Missense mutations appeared in 74% of cases compared with deletions and insertions (20%), nonsense (4%) and splice site (2%) mutations. The majority (243 of 268) of mutations were located in the DNA-binding domain. Transitions were found in 131 of 268 mutations, with only 41 occurring at methylated CpG sites (15%), suggesting that transitions at CpGs are uncommon. The codons most frequently mutated were at positions 175, 179, 248 and 273; in addition, we detected a common 2-nt deletion in the codon 209. Most mutations (199 of 259) were accompanied by deletion of the other allele (17p-). Interestingly, trisomy 12 (without 17p-) was only found in one of 60 cases with TP53 mutation (without 17p-) compared with 60 of 16 in the cohort without mutation (P=0.006). The mutational profile was not different in the cohorts with and without previous therapy, suggesting that the mechanism underlying the development of mutations may be similar, independent of treatment.

Sequential cycles of high-dose chemotherapy with dose escalation of carboplatin with or without paclitaxel supported by G-CSF mobilized peripheral blood progenitor cells: a phase I/II study in advanced ovarian cancer.

To assess high-dose carboplatin chemotherapy with or without paclitaxel with filgrastim mobilized peripheral blood progenitor cell (PBPC) support in a phase I/II study, a total of 21 patients with mostly chemonaive disease received four cycles of high-dose chemotherapy. Cycle 1 (cyclophosphamide, 6 g/m2) was followed by two cycles of carboplatin (1600 mg/m2 or 1800 mg/m2). Cycle 4 consisted of carboplatin (1600 mg/m2), etoposide (1600 mg/m2), and melphalan (140 mg/m2). Further chemotherapy intensification was achieved by adding paclitaxel (175 mg/m2) to all cycles with a fixed carboplatin dose (1600 mg/m2). Ototoxicity was dose-limiting for escalation of sequential cycles of carboplatin. Grade 2 and grade 3 ototoxicity, hearing loss not requiring a hearing aid, or hearing loss correctable with a hearing aid, was observed with carboplatin at 1800 mg/m2. The maximum tolerated dose (MTD) of sequential carboplatin, therefore, was identified in this study as 1600 mg/m2. After cycles 1, 2, 3 and 4 the median duration of leukopenia (<1.0x10(9)/l) was 7, 4, 4 and 6 days. Severe grade 3 and 4 infections were seen in only 7% of cycles. Of the 21 patients evaluable for disease response, 57% had complete remissions and 43% experienced partial remissions resulting in an overall response rate of 100%. The median progression-free survival is 25 (15-36) months, the median overall survival 36.5 (15-38) months. Most patients were suboptimally debulked or had bulky residual disease at the start of chemotherapy. Sequential high-dose chemotherapy to a maximum dose of 1600 mg/m2 carboplatin is effective and feasible. A randomized, prospective trial comparing sequential high-dose chemotherapy with optimal standard chemotherapy is now warranted.

The use of CD34+-selected PBPC after high-dose chemotherapy in breast cancer patients is associated with prolonged recovery time and increased infectious complications.

High-dose chemotherapy with autologous stem cell rescue can result in autotransplantation of tumor cells. A possible approach to reduce tumor cell contamination is the positive selection of CD34+ PBPC, but this might be associated with a prolonged recovery time as well as an increased risk of infectious complications because of the loss of committed progenitor cells. To investigate this aspect, we compared two sequentially treated cohorts of high-risk breast cancer patients. Both groups received the same high-dose chemotherapy regimen followed by autologous peripheral stem cell transplantation. Group I received CD34+-selected blood progenitor cells, and group II received nonselected blood progenitor cells. We compared these two identically treated groups with regard to recovery time, need for blood products, infectious complications, need for antibiotic treatment, and length of the transplantation-related hospital stay. We found a prolonged recovery time for neutrophils up to 0.5 x 10(9)/L (14 days in the selected group/10 days in the nonselected group) and platelets up to 30 x 10(9)/L (29/12 days), associated with an increased requirement for RBC transfusions (5/3 U) and platelet transfusions (10/2 U). The rate of severe infectious complications (2/0), the need for nonprophylactic antibiotic treatment (15/10), and the length of the hospital stay (25/21 days) in group I were also increased. We conclude that positive selection of PBPC should not be used routinely until randomized studies show a clear long-term benefit of using CD34+-selected stem cell products in breast cancer patients.