Biomedical subjects

Ulf-Hakan Stenman

Publications and source records attributed to Ulf-Hakan Stenman.

4 recordsLinked to original sources

PubMed2003

Immunopeptidometric assay for enzymatically active prostate-specific antigen.

BACKGROUND: Determinations of certain forms of prostate-specific antigen (PSA) have been shown to increase the specificity for prostate cancer (PCa). One such variant, proteolytically active PSA, is a potentially useful tumor marker, but it is not specifically recognized by antibodies. Using phage display libraries, we previously identified a "family" of peptides that bind specifically to active PSA. We used these to develop an immunopeptidometric assay (IPMA) that specifically detects this form of PSA. METHODS: Microtitration plates coated with a PSA antibody were used to capture PSA, and a PSA-binding glutathione S-transferase (GST) fusion peptide was used as a tracer. Bound tracer was detected with an antibody to GST labeled with a europium chelate. PSA isoenzymes with high and low enzymatic activity were used to study binding specificity. RESULTS: The IPMA detected enzymatically active PSA but not internally cleaved PSA and pro-PSA, which are enzymatically inactive. The assay detected 1-10% of free PSA in serum from PCa patients. CONCLUSIONS: Peptides identified by phage display can be used to develop assays with unique specificities for enzymatically active PSA. IPMA represents a new assay principle with wide potential utility.

Female↗

PubMed2003

Expression of the free beta-subunit of human chorionic gonadotropin in renal cell carcinoma: prognostic study on tissue and serum.

Expression of the free beta-subunit of human chorionic gonadotropin (hCGbeta) in malignant tumors is frequently associated with aggressive disease. We have shown previously that the pretreatment serum concentration of hCGbeta is an independent prognostic variable in patients with renal cell carcinoma (RCC). We now compare the serum levels with the expression of hCGbeta antigen and mRNA in tumor tissue and studied whether these are associated with the clinical outcome. Serum samples were collected before surgery from patients with RCC (n = 256) and from 84 apparently healthy controls. HCGbeta in serum was measured by a time-resolved immunofluorometric assay. Tissue expression was detected by immunohistochemical staining of a tissue microarray (TMA) comprising 229 samples, and in selected cases by reverse transcription polymerase chain reaction (RT-PCR) of hCGbeta mRNA (n = 20) from tumor tissue. The prognostic value of hCGbeta in serum and tissue and the association with usual clinicopathological variables was analyzed by the Kaplan-Meier method, the log-rank test, Cox multiple hazard regression, Mann-Whitney U-test or Kruskal-Wallis test. The serum concentrations of hCGbeta were increased in 27% of the RCC patients and patients with increased hCGbeta levels had significantly shorter survival time than those with levels below the median (cut-off 1.2 pmol l(-1), p = 0.0044). HCGbeta antigen was detected in 15% (35 of 229) of the tumors by immunohistochemistry, and hCGbeta mRNA in 8 of 20 samples (40%) by RT-PCR. Tissue positivity for hCGbeta antigen was not associated significantly with mRNA expression, serum concentrations of hCGbeta or survival. In multivariate analysis tumor stage, grade, size and serum hCGbeta were independent prognostic variables. The serum concentration of hCGbeta is an independent prognostic variable in RCC. Tissue expression of hCGbeta detected by immunohistochemistry occurs in 15% of RCCs but it is not significantly associated with prognosis. Expression at the mRNA level seems to be associated with other predictors of adverse outcome.

Adult↗

PubMed2003

Human kallikrein 6 (hK6): a new potential serum biomarker for diagnosis and prognosis of ovarian carcinoma.

PURPOSE: The discovery of new ovarian cancer biomarkers that are suitable for early disease diagnosis and prognosis may ultimately lead to improved patient management and outcomes. PATIENTS AND METHODS: We measured, by immunoassay, human kallikrein 6 (hK6) concentration in serum of 97 apparently healthy women, 141 women with benign abdominal diseases, and 146 women with histologically proven primary ovarian carcinoma. We then calculated the diagnostic sensitivity and specificity of this test and examined the association of serum hK6 concentration with various clinicopathologic variables and patient survival. RESULTS: Serum hK6 concentration between normal and benign disease patients was not different (mean, 2.9 and 3.1 micro g/L, respectively). However, hK6 in presurgical serum of ovarian cancer patients was highly elevated (mean, 6.8 micro g/L; P <.001). Serum hK6 decreased after surgery (to a mean of 3.9 micro g/L) in 68% of patients. The diagnostic sensitivity of serum hK6 at 90% and 95% specificity is 52% and 47%, respectively, in the whole patient population. For early stage disease (stage I or II), sensitivity is approximately 21% to 26%. When combined with CA-125, at 90% specificity, sensitivity increases to 72% (for all patients) and to 42% in stage I or II disease. Serum hK6 concentration correlates moderately with CA-125 and is higher in patients with late-stage, higher-grade disease and in patients with serous histotype. Preoperative serum hK6 concentration is a powerful predictor of disease-free and overall survival in both univariate and multivariate analyses. CONCLUSIONS: Serum hK6 concentration seems to be a new biomarker for ovarian carcinoma and may have value for disease diagnosis and prognosis.

Adult↗

PubMed2003

The serum concentration of human kallikrein 10 represents a novel biomarker for ovarian cancer diagnosis and prognosis.

Human kallikrein 10 (hK10) is a secreted serine protease that is highly expressed in ovarian tissue. We hypothesized that hK10 might represent a novel serological marker for ovarian cancer. We quantified by immunoassay, hK10 in sera from 97 normal women (controls), 141 patients with benign gynecologic diseases, and 146 patients with ovarian cancer. We then examined the diagnostic and prognostic value of this measurement in ovarian cancer. We found that normal serum hK10 ranged from 50 to 1040 ng/liter (mean = 439 ng/liter). hK10 concentration is significantly elevated in serum of presurgical ovarian cancer patients (range: 106-11,746 ng/liter; mean = 1067 ng/liter) but not in serum of patients with benign gynecologic diseases (range: 120-1200 ng/liter; mean = 447 ng/liter). When a cutoff of 700 ng/liter was selected (diagnostic specificity = 90%), the diagnostic sensitivity for ovarian cancer is 54%. About 35% of CA125-negative ovarian cancer patients (CA125 < 23 kU/liter) were hK10 positive at 90% specificity. In patients with stage I/II ovarian cancer, use of these two markers in combination results in a 21% increase in sensitivity, at 90% specificity, compared with CA125 alone. High serum hK10 was strongly associated with serous epithelial type, late-stage, advanced grade, large residual tumor (>1 cm), suboptimal debulking, and no response to chemotherapy (all Ps < 0.001). In univariate Cox survival analysis, high serum hK10 is associated with increased risk for relapse and death (hazard ratio = 2.59 and 3.15, respectively, P </= 0.003). This prognostic value remains significant for overall survival in the multivariate analysis. Kaplan-Meier survival curves demonstrated similar findings. Serum hK10 represents a novel biomarker for ovarian cancer. We conclude that preoperative serum hK10 concentration is a strong and independent unfavorable prognostic marker for ovarian cancer.

Adult↗