Nonspecific cross-reacting antigen 50/90 is elevated in patients with breast, lung, and colon cancer.
A total of 22 genes have been identified in the carcinoembryonic antigen (CEA) gene family. The protein products of this family are highly homologous and include CEA, biliary glycoprotein, nonspecific cross-reacting antigen 50/90 (NCA 50/90), NCA 95, and pregnancy-specific beta-glycoprotein. We used a monoclonal antibody with high affinity to develop a specific enzyme-linked immunosorbent assay (ELISA) method for NCA 50/90 in serum and plasma. Our calibrators were based on affinity-purified recombinant protein from a baculovirus expression system. No significant reactivity with purified CEA, recombinant NCA 95, or recombinant biliary glycoprotein was found by Western blot analysis or in the ELISA method. Only 1 of 15 sera from pregnant women (chorionic gonadotropin > 1000 ng/ml) was positive in the NCA 50/90 ELISA, suggesting that this method does not detect pregnancy-specific glycoprotein. A cutoff value of 18 ng/ml was established based on the 95% value of serum and plasma from 147 healthy volunteers. Only 3 of 31 serum and plasma samples from patients with clinically inactive breast cancer were elevated above the cutoff value, but 44% of 136 samples from patients with clinically active breast cancer were positive. NCA 50/90 measurements were elevated in 7 of 25 patients with active breast cancer whose CEA and CA 15-3 values were below cutoff, and NCA 50/90 values do not correlate with CEA in breast cancer. In addition, we found sensitivities of 70, 39, and 42% for lung cancer, colon cancer, and leukemia, respectively. The sensitivity for non-small cell lung cancer was 85%, however, compared to 50% for small cell lung cancer. Serum from leukemia patients showed an overall sensitivity of 43%, but 71% (10 of 14) sera from patients with chronic myelogenous leukemia were positive compared to, for example, chronic lymphocytic leukemia where 0 of 7 sera had NCA 50/90 values above the cutoff. These studies suggest that NCA 50/90 may have clinical utility in the management of patients with a variety of cancers.
Allard
W J
WJ
Molecular Diagnostics Group, Immunodiagnostics Business Unit, Miles Diagnostics, Tarrytown, New York 10591.
Neaman
I E
IE
Elting
J J
JJ
Barnett
T R
TR
Yoshimura
H
H
Fritsche
H A
HA
Yeung
K K
KK
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000915:Antibody Affinity; D000918:Antibody Specificity; D015214:Antigens, Differentiation, Myelomonocytic / Q000097:blood*; D000951:Antigens, Neoplasm / Q000032:analysis / Q000097:blood*; D000954:Antigens, Surface / Q000097:blood; D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000097:blood*; D015815:Cell Adhesion Molecules; D003110:Colonic Neoplasms / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007700:Kinetics; D008175:Lung Neoplasms / Q000097:blood*; D008562:Membrane Glycoproteins / Q000032:analysis / Q000097:blood*; D051379:Mice; D008807:Mice, Inbred BALB C; D012016:Reference Values
D000911:Antibodies, Monoclonal; D015214:Antigens, Differentiation, Myelomonocytic; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules; D008562:Membrane Glycoproteins