Interchangeability and diagnostic accuracy of two assays for total and free prostate-specific antigen: two not always related items.

The variation between different PSA assays seems to influence the interpretation of individual PSA values and the clinical decisions about prostate cancer. One reason for this variability could be the different reactivity of antibodies for the various molecular forms of serum PSA; as a result, samples containing the same amount of tPSA but different proportions of fPSA can produce very different values. In this study, serum samples were collected prospectively from 152 consecutive patients referred to 2 institutions (Regional Hospital, Venice, 90 subjects; San Bortolo Hospital, Vicenza, 62 subjects) for PSA elevation and/or symptoms. Serum samples were assessed according to the manufacturers' instructions on the following 2 analyzers: the Immulite 2000 assay (Diagnostic Products Corporation, Los Angeles, USA), which measures tPSA and fPSA, and the ADVIA Centaur (Bayer Diagnostics, Tarrytown, USA), which assays tPSA and cPSA. cPSA values were transformed into fPSA by the equation fPSA=tPSA-cPSA. When taking Immulite tPSA and f/tPSA values as 100%, ADVIA Centaur values were 92.6% and 122%, respectively, which means that 20% of patients would be classified differently according to the traditional biopsy cutoff. In conclusion, there are considerable differences between the 2 methods, which could affect clinical decisions.

Gefitinib (ZD1839) combined with weekly epirubicin in patients with metastatic breast cancer: a phase I study with biological correlate.

PURPOSE: Epidermal growth factor receptor (EGFR) is overexpressed in approximately 50% of invasive breast carcinomas and it is correlated with hormone resistance and poor prognosis. EGFR suppression by gefitinib, a quinazoline derivative that inhibits phosphorylation of the specific receptor, represents a novel therapeutic strategy. A dose-finding study was performed to evaluate the combination of gefitinib with weekly epirubicin in patients with pretreated metastatic breast cancer. METHODS: Fifteen patients were enrolled at four sequential dose levels. Gefitinib was administered orally, at the fixed daily dose of 250 mg. The starting dose of epirubicin was 20 mg/m2. Escalating dose levels of epirubicin were planned by increments of 5 mg/m2 per level, up to the maximum tolerated dose (MTD). Pharmacodynamic studies were performed by determining serum and tissue ERBB2 and EGFR. RESULTS: At the first three dose levels tested no patient experienced a dose-limiting toxicity (DLT). In cohort 4, two patients experienced DLTs (grade 4 dyspnea and asthenia, grade 3 diarrhea and thrombocytopenia) identifying the MTD of epirubicin as 35 mg/m2. Of the 14 cases assessable for response, partial response was documented in two patients, and stable disease in seven, giving an overall disease control rate of 64.2%. The comparison of pre- and post-therapy ERBB2 and EGFR values was not statistically significant between the subgroups of patients regarding responsiveness to treatment. CONCLUSIONS: The recommended dose of epirubicin for phase II studies is 30 mg/m2 in combination with gefitinib at the daily dose of 250 mg. Pharmacodynamic studies did not identify any biomarker predictive of response.

Free DNA in urine: a new marker for bladder cancer? Preliminary data.

The aim of the present preliminary study was to investigate the presence of free DNA (FDNA) in urine as a possible marker for the diagnosis of bladder cancer. Naturally voided morning urine specimens were collected from 57 patients with suspected bladder cancer before cystoscopy. A standard urine test was performed; the specimens were then processed in order to obtain a quantitative evaluation of the presence of free DNA in the urine. Twenty-two patients were excluded from the study because they had leukocyturia and/or bacteriuria. Free DNA concentrations higher than 250 ng/mL were found in all 16 patients showing bladder cancer at cystoscopy and in seven (36.8%) of the 19 patients with negative cystoscopy. Urinary FDNA seems to have an excellent sensitivity: we observed no false negative cases and 36.8% false positive cases. By contrast, only 6.25% of the bladder cancer patients had positive urine cytology. Our results seem promising, although further studies and larger numbers are needed to define urinary free DNA as a reliable marker of bladder cancer.

Evaluation of HER-2/neu in serum and tissue of primary and metastatic breast cancer patients using an automated enzyme immunoassay.

Serum HER-2/neu concentrations were evaluated in 172 healthy subjects, 176 primary and 55 metastatic breast cancer patients, employing a new automated assay (Bayer Immuno 1 serum HER-2/neu). Using 13 ng/mL as the cutoff, abnormal HER-2/neu serum levels were found in 8% (14/176) of primary and 50.9% (28/55) of metastatic breast cancer patients. Both in primary and metastatic breast cancer a significant relationship was found with the stage of the disease when serum HER-2/neu was considered as a categorized variable (p=0.0003 and p=0.02, respectively), but not when it was taken as a continuous variable (p=0.247 and p=0.146, respectively). Moreover, we evaluated the correlation between Immuno 1 HER-2/neu and Oncogene Research Products ELISA assay in 53 normal subjects, 46 primary and 34 metastatic breast cancer patients. The correlation was relatively good (p<0.0001), although substantial differences could be found in single cases. The Immuno 1 assay was also evaluated for the first time in breast cancer tissue. The method, which showed good performance both in terms of imprecision and linearity, was used to measure HER-2/neu protein in 140 cytosol samples from primary breast cancer tissue and in homogenates from 40 matched cases. The correlation between the two matrixes was very close (p<0.0001). By contrast, no correlation was found between serum and matched cytosol (p=0.101) or homogenate samples (p=0.511).