Shed HER2 surrogacy evaluation in primary breast cancer patients: a study assessing tumor tissue HER2 expression at both extracellular and intracellular levels.

The aim of the present study was to investigate serum HER2 extracellular domain (ECD) as a putative surrogate marker of the shedding phenomenon of HER2 receptor from the tumor tissue of primary breast cancer (BC) patients. A pilot retrospective study was conducted on 100 matched serum and tissue samples from patients with node-positive primary BC, stage II/III. Analysis of association and concordance between serum HER2 ECD levels (measured by chemiluminescence immunoassay) and the expression in matched tumor tissue of HER2 ECD and intracellular receptor domain (ICD) (determined by immunohistochemistry) were performed. The median serum HER2 ECD level was 9.4 ng/ml and cutoff values were set at 15.2 ng/ml or 13.0 ng/ml. HER2 ICD and ECD were overexpressed in tumor tissue of 19.8% and 6.9% of patients, respectively. Statistically significant associations were found between serum HER2 ECD levels and tissue expression of both HER2 ICD and ECD (p < .001; Fisher analysis). Moreover, strong concordances were found between serum HER2 ECD levels and tissue expression of HER2 ICD or ECD (cutoff 15.2 ng/ml: 80 and 92.5%, respectively). Our findings support a role for serum HER2 ECD as a surrogate marker of tissue HER2 status in primary BC, both for HER2 ICD or ECD expression.

Evaluating serum insulin-like growth factor 1 and insulin-like growth factor binding protein 3 as markers in prostate cancer diagnosis.

BACKGROUND: Prostate-specific antigen (PSA) lacks specificity and sensitivity in discriminating prostate cancer (PCa) from benign prostatic hyperplasia (BPH) when the total PSA (tPSA) level is between 4 and 10 ng/mL. It remains to be investigated if additional tumor-associated molecules may improve the PCa diagnostic accuracy. The aim of the present study was to investigate whether serum levels of insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3) and their combinations with PSA may enhance the diagnosis of PCa. METHODS: Serum tPSA and free PSA (fPSA) levels were measured using an automated chemiluminescence-based method. IGF1 and IGFBP3 levels were evaluated by radioimmunoassays in a prospectively and consecutively enrolled subset of 149 patients with tPSA ≤10 ng/mL made up of patients with benign prostatic hyperplasia (BPH; n = 113) and PCa (n = 36). RESULTS: IGF1 and IGFBP3 serum levels did not significantly differ between the PCa and BPH groups. No important correlation was found between the IGF molecules and PSA isoforms in both groups. Statistical analysis of the combination of markers indicated that only the free/total PSA ratio (f/tPSA%) was informative and independent in predicting the presence of PCa, considering that for high values of this percentage (17%) the probability of finding PCa decreased. Receiver operating characteristics areas under the curve (AUC) for IGF1 and IGFBP3 were not informative (AUC ~0.5 in both cases) contrary to the AUC for f/tPSA% (AUC = 0.689, p = 0.0002). CONCLUSIONS: The present study showed that neither IGF1 and IGFBP3 alone nor in combination with PSA enhance the diagnostic performance of PSA in PCa.

An epidemiology-based model as a tool to monitor the outbreak of inappropriateness in tumor marker requests: a national scale study.

BACKGROUND: Evaluation of appropriateness of laboratory tests on the basis of individual requests remains a serious problem as the clinical question is usually not reported with the test order. This study explored the comparison of the rate of tumor marker orders with cancer prevalence as a putative indicator of inappropriateness. METHODS: Tumor marker orders (2011 and 2012) were obtained from the Ministry of Health and cancer prevalence from the Italian Association of Cancer Registries. The rate of tumor marker orders was matched with demographic data and tumor prevalence and examined by using the confidence interval approach. Region-to-region and year-to-year variations were also examined. Focus was placed on CEA, CA125, CA19.9 and CA15.3. RESULTS: Tumor markers ordered in Italy were 13,207,289 in 2012 (221.3/1000 individuals). Given an estimated prevalence of 2,243,953 cancer cases, 7.04 tumor markers appear to be requested for each prevalent case of epithelial cancer per year. The rate of requests of CEA, CA125, CA19.9 and CA15.3 (in aggregate 5,834,167 requests in 2012, 44.2% of total) from the first and the last ranked region (96 and 244/1000 individuals) are significantly different (p<0.01). Region-to-region differences do not correspond to any known variation of prevalence in the different regions. CONCLUSIONS: The developed approach provides a proxy indicator of inappropriateness showing that tumor markers are overused in Italy and their ordering pattern is not related to tumor prevalence. The model is suitable to be validated in other laboratory tests used in diseases whose prevalence is known.

An epidemiology-based model to estimate the rate of inappropriateness of tumor marker requests.

BACKGROUND: Appropriateness of tumor markers (TMs) has been retrospectively studied in limited patients' series, matching the requests to clinical records. Methods to monitor appropriateness suitable for use on a large scale are required. This study aims to establish and validate an innovative model to estimate appropriateness based on the comparison between the number of TMs requested and the expected requests inferred from epidemiological data. METHODS: The number of CA15.3, CA19.9 and CA125 requests theoretically expected according to the epidemiology of malignancies in a known geographic area (2 Italian regions) was compared with the number of TMs actually requested - the surveyed requests projected on a regional scale - during a given time span (1 year). The expected number of requests was calculated comparing TMs recommended by guidelines in different clinical scenarios with the prevalence or incidence figures of the examined diseases (carcinomas of breast, pancreas and biliary tract, ovary and endometrium). RESULTS: Suitability of the model was demonstrated with the analysis of 1,891,070 TM requests surveyed in 66 laboratories from Veneto and Tuscany regions. The percentage difference over the total of expected TMs (delta%) ranged from -6.9% for CA15.3 to +1022.6% for CA19.9 in Veneto and from +35.7% for CA15.3 to +1842.6% for CA19.9 in Tuscany. CONCLUSIONS: The presented model was effective in demonstrating higher than expected TM request rates, possibly associated with inappropriate use. Moreover, it can be applied on a large scale survey setting since it circumvents the unavailability of clinical information on test orders.