Evaluation of serum sialic acid and carcinoembryonic antigen for the detection of early-stage colorectal cancer.

Various expressions of elevated serum sialic acid (total sialic acid, TSA: lipid-associated sialic acid, LASA; LASA/TSA; TSA normalized to total protein, TSA/TP) have been evaluated and compared with increased serum carcinoembryonic antigen (CEA) levels for the detection of early-stage colorectal cancer. This evaluation was done blindly on a coded panel of 320 sera from staged colorectal cancer patients and controls provided by the Mayo Clinic--National Cancer Institute Diagnostic Bank. Unlike the findings of a previous preliminary study (Tautu et al., JNCI 80:1333-1337, 1988), the ratio of LASA/TSA was not useful for detecting early-stage (Dukes A and B) colorectal cancer. However, TSA and TSA/TP values were significantly elevated in each colorectal cancer subgroup compared with normal controls. TSA and TSA/TP values displayed a marginally better discriminatory power than CEA values in the case of Dukes A subgroup with respect to normal controls. CEA still appears to be the best single overall marker for discriminating between colorectal cancers and controls. However, multiple marker analysis using CEA and TSA (and related markers) appears to be more sensitive than CEA alone for detecting colorectal cancer.

Multiple markers for lung cancer diagnosis: validation of models for localized lung cancer.

Sera from 71 patients with localized lung cancer, from 70 normal controls, and from 73 patients with benign lung diseases were analyzed for 10 substances to detect lung cancer: ferritin, lipid-bound sialic acid, total sialic acid, beta 2-microglobulin, lipotropin, the alpha and beta subunits of human chorionic gonadotropin, calcitonin (two assays), parathyroid hormone, and carcinoembryonic antigen (CEA). Individual markers were studied, and optimal combinations of markers were sought for discriminating patients with localized lung cancer from normal controls and from patients with benign lung disease. Both logistic regression and recursive partitioning methods for discrimination were tried. The best rules involved only CEA and ferritin for discriminating patients with lung cancer from normal controls, and CEA and age for discriminating patients with lung cancer from those with benign lung diseases. The performance of these rules was validated on an independent serum panel containing sera from 56 patients with localized lung cancer, 75 normal controls, and 75 patients with benign lung diseases. Three rules designed to achieve 95% specificity against normal controls attained 14%-36% sensitivity for localized lung cancer in the validation panels, whereas three rules designed to achieve 95% specificity against benign lung diseases attained 30%-39% sensitivity. Some aspects of potential clinical applications are discussed.

Multiple markers for lung cancer diagnosis: validation of models for advanced lung cancer.

Sera from 171 patients with advanced lung cancer, from 110 normals, and from 123 subjects with benign respiratory diseases were analyzed for 10 substances to detect lung cancer: ferritin, lipid-bound sialic acid, total sialic acid, beta 2-microglobulin, lipotropin, the alpha and beta subunits of human chorionic gonadotropin, calcitonin (two assays), parathyroid hormone, and carcinoembryonic antigen. Individual markers were studied, and optimal combinations of markers were sought for discriminating lung cancer patients from normals and from patients with benign lung disease. Numerous methods for combining the markers were examined, but the methods of logistic regression and recursive partitioning were finally adopted. The best discrimination rules we could find used only carcinoembryonic antigen (CEA) and total sialic acid (TSA). The performance of these rules was validated on an independent serum panel containing sera from 68 patients with advanced lung cancer, from 40 normals, and from 52 patients with benign respiratory disease. The combination rules based on TSA and CEA performed better than a rule based on CEA alone. Logistic discrimination rules with TSA and CEA that were designed to have 95% specificity achieved 54% sensitivity for discriminating advanced lung cancer from normal controls and 52% sensitivity for discriminating advanced lung cancer from controls with benign disease. Some aspects of clinical applicability are discussed, including planned studies for localized lung cancer and the requirement for further testing in specific clinical settings.

Serum bank for biological markers for breast cancer.

A bank of serum specimens from women at varying risks of breast cancer has been established. Panels of test specimens can be secured by qualified investigators to evaluate newly discovered biological markers for breast cancer, to verify preliminary data, and to compare performance of established assays among different laboratories. Panels consisting of coded 1-ml vials of sera will be sent upon request to approved investigators. The procedure for application for serum panels is described.