PTEN mutation, EGFR amplification, and outcome in patients with anaplastic astrocytoma and glioblastoma multiforme.

BACKGROUND: Survival of patients with anaplastic astrocytoma is highly variable. Prognostic markers would thus be useful to identify clinical subsets of such patients. Because specific genetic alterations have been associated with glioblastoma, we investigated whether similar genetic alterations could be detected in patients with anaplastic astrocytoma and used to identify those with particularly aggressive disease. METHODS: Tissue specimens were collected from 174 patients enrolled in Mayo Clinic Cancer Center and North Central Cancer Treatment Group clinical trials for newly diagnosed gliomas, including 63 with anaplastic astrocytoma and 111 with glioblastoma multiforme. Alterations of the EGFR, PTEN, and p53 genes and of chromosomes 7 and 10 were examined by fluorescence in situ hybridization, semiquantitative polymerase chain reaction, and DNA sequencing. All statistical tests were two-sided. RESULTS: Mutation of PTEN, amplification of EGFR, and loss of the q arm of chromosome 10 were statistically significantly less common in anaplastic astrocytoma than in glioblastoma multiforme (P =.033, P =.001, and P<.001, respectively), and mutation of p53 was statistically significantly more common (P<.001). Univariate survival analyses of patients with anaplastic astrocytoma identified PTEN (P =.002) and p53 (P =.012) mutations as statistically significantly associated with reduced and prolonged survival, respectively. Multivariate Cox analysis of patients with anaplastic astrocytoma showed that PTEN mutation remained a powerful prognostic factor after adjusting for patient age, on-study performance score, and extent of tumor resection (hazard ratio = 4.34; 95% confidence interval = 1.82 to 10.34). Multivariate classification and regression-tree analysis of all 174 patients identified EGFR amplification as an independent predictor of prolonged survival in patients with glioblastoma multiforme who were older than 60 years of age. CONCLUSION: PTEN mutation and EGFR amplification are important prognostic factors in patients with anaplastic astrocytoma and in older patients with glioblastoma multiforme, respectively.

Small cell architecture--a histological equivalent of EGFR amplification in glioblastoma multiforme?

Although there is much written about the molecular definitions of "primary" glioblastomas (GBM), there is little known about the histological features of this predominant subtype. We hypothesized that the "small cell architecture" would represent a histological feature of most primary GBMs. This was tested by comparing the presence of the small cell phenotype with the presence or absence of amplification of the epidermal growth factor receptor (EGFR), a common event in primary GBMs. After a pilot study that found a correlation between this small cell phenotype and EGFR amplification, we selected 9 pure small cell GBMs (SCGBM) and 12 non-SCGBMs to be studied for EGFR amplification by fluorescence in situ hybridization (FISH). In this set of 21 cases, 8 of 9 SCGBMs and 5 of 12 non-SCGBMs were amplified for EGFR. We then correlated the EGFR status of 79 GBMs unselected for their histological features from a set that had been previously characterized in regard to EGFR amplification. Fourteen of 21 (67%) exclusively small cell neoplasms, 8 of 25 (32%) GBMs with both small cell and non-small cell areas, and 3 of 33 (9%) non-small cell GBMs were amplified for EGFR (p = 0.0004 with an exact test). We conclude that EGFR amplification is associated with a small cell phenotype in GBMs and that SCGBMs are an important component of "primary" GBMs.

The effect of trimoprostil (trimethyldesoxy prostaglandin E2) on the intrauterine pressure in women.

Prostaglandin E2 is uterotonic. Trimoprostil, a prostaglandin E2 analog, is a gastric antisecretory and cytoprotective agent. The effects of single doses of 0, 0.125, 0.75, and 3.0 mg trimoprostil on intrauterine pressure were measured in a double-blind, crossover study in eight surgically sterile women. The 3 mg dose was not tolerated because of abdominal cramps. The other doses caused a dose-related increase in resting uterine tone and peak pressure with peak effect occurring between 30 and 60 minutes after administration with a duration of about 120 minutes. No effects on the frequency of uterine contractions occurred. Peak mean tone increased from 11.0 to 71.2 mm Hg (p less than 0.01) and peak pressure from 24.6 to 125.1 mm Hg (p less than 0.01) after placebo compared with the 1.5 mg dose. Adverse reactions included abdominal pain that correlated with an increase in intrauterine pressure and tone.

The influence of reduced dietary fat absorption induced by orlistat on the pharmacokinetics of digoxin in healthy volunteers.

To assess the influence of an orlistat-induced reduction in dietary fat absorption on the pharmacokinetics of digoxin, an open-label, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers. Each subject received single 0.4-mg doses of digoxin (soft gelatin capsules) administered orally on the fourth day of orlistat (120 mg three times daily for 6 days) and placebo (three times daily for 6 days) treatment, separated by at least an 11-day washout period. Serial blood samples were collected before and at appropriate intervals after each digoxin dose to determine plasma concentrations of unchanged digoxin. The 90% confidence intervals for the ratio of geometric least-squares means (for Cmax, AUC0-48, AUC0-t, and AUC) and for the difference of arithmetic least-squares means (for tmax and lambda z) indicate that the pharmacokinetics of digoxin was not altered by treatment with orlistat. This results suggests that a approximately 30% reduction in dietary fat absorption will not change the efficacy of digoxin in cardiac patients.

The effect of orlistat on the pharmacokinetics and pharmacodynamics of warfarin in healthy volunteers.

To assess the effect of orlistat on the pharmacokinetics and pharmacodynamics of warfarin, a third-party blind, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers. Each participant received single 30-mg oral doses of racemic warfarin sodium (Coumadin; DuPont Pharma, Wilmington, DE) administered on the eleventh day of treatment with 120 mg orlistat (treatment A) and placebo (treatment B) three times a day for 16 days; the two treatments were separated by a 3-week washout period. Serial blood samples were collected before and at appropriate intervals after each dose of warfarin to determine plasma concentrations of R-warfarin and S-warfarin and blood prothrombin time (PT) and plasma Factor VII concentration. In addition, serum concentrations of vitamin K1 and its epoxide and of osteocalcin and its undercarboxylated form were measured before breakfast on days -7, 1, 4, 6, and 10. Equivalent results between treatments with orlistat and placebo were found with regard to all pharmacokinetic parameters of R- and S-warfarin (except for time to maximum concentration of R-warfarin). Pharmacodynamic parameters of warfarin (PT and Factor VII) and vitamin K nutritional status parameters (ratios of vitamin K1 to vitamin K1 epoxide and undercarboxylated osteocalcin to osteocalcin) also were unaltered by orlistat. Orlistat administered at doses of 120 mg three times daily did not significantly alter the pharmacokinetics and pharmacodynamics of a single 30-mg oral dose of warfarin in healthy volunteers.

Pharmacokinetics of recombinant human interferon-alpha 2a combined with 5-fluorouracil in patients with advanced colorectal carcinoma.

We evaluated the pharmacokinetics of 5-fluorouracil (5-FU) combined with recombinant human interferon (IFN)-alpha 2a in 10 previously untreated patients with advanced colorectal carcinoma. 5-FU was administered as a continuous i.v. infusion, 750 mg/m2/day for 5 days during week 1. One s.c. injection of IFN-alpha 2a, 9 x 10(6) IU, was administered during week 2. Beginning with week 3, a continuous i.v. infusion of 5-FU 750 mg/m2/day for 5 days was administered in combination with IFN-alpha 2a, 9 x 10(6) IU s.c. three times per week. The combination of 5-FU and IFN-alpha 2a was continued every other week until either 3 months after complete remission or tumor progression. No grade 4 toxicity was observed. Granulocytopenia (two patients), leukopenia (one patient), thrombocytopenia (one patient), stomatitis (two patients), fatigue (one patient) and hand-foot syndrome (one patient) were the major (grade 3) toxic reactions encountered. Overall, one complete and six partial responses were noted. The results of the paired t-test showed no statistically significant differences between the means of the two treatments, 5-FU and 5-FU plus IFN-alpha 2a, with respect to the steady-state plasma concentration, area under the concentration-time curve, total body clearance, or steady-state volume of distribution of 5-FU, or the serum concentration of IFN. We conclude that 5-FU and IFN-alpha 2a do not interact pharmacokinetically at the doses and schedules in the regimen studied.