Carcinoembryonic antigen in amniotic fluid

Do the levels of tumor makers or proinflammatory cytokines in mid-trimester cervical fluid predict early-stage cervical shortening?

AIM

In the present study, we aimed to assess the biomarkers in mid-trimester cervical fluid that can predict early stage cervical shortening.

MATERIAL AND METHODS

We obtained cervical swab specimens from 96 gravidas, after which the cervical length was measured, at approximately 20 weeks of gestation. Cervical length was measured again at 4 weeks after the initial examination. Cervical shortening was noted in 20 women between 20 and 24 weeks of gestation (group A), whereas no cervical shortening was noted in 76 women (group B). We evaluated the use of the levels of tumor markers, proinflammatory cytokines, and matrix metalloproteinase-8 (MMP-8) as candidate biomarkers. CA-125 and carcinoembryonic antigen levels were determined by using an automatic immunoassay system in both groups. Furthermore, IL-1β, IL-8, tumor necrosis factor-α, and MMP-8 levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

The levels of inflammatory cytokines and MMP-8 did not differ between the two groups, and were not correlated with cervical length or the change in cervical length. Although CA-125 and carcinoembryonic antigen levels were higher in group A, they were not statistically significant (P = 0.304 and 0.092, respectively).

CONCLUSION

Early stage cervical shortening in mid-trimester was not associated with an increase in the levels of tumor markers or proinflammatory cytokines in cervical fluid.

Tumor Markers In Biological Fluids Associated With Pregnancy

Proteins that are expressed by both malignant and healthy fetal tissues are recognized as oncofetal. These antigens are associated with cell proliferation and differentiation and are produced in high concentrations in pregnancy and malignancy. Their biological role in malignancy is the suppression of the host's immune system, while in pregnancy they affect the maternal immune response, generating maternal tolerance toward the embryo. This review describes the levels of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), carcinoembryonic antigen (CEA), cancer antigen 125 (CA 125), squamous cell carcinoma antigen (SCC), cancer antigen 15-3 (CA 15-3), mucin-like carcinoma-associated antigen (MCA), tissue polypeptide-specific antigen (TPS), carbohydrate antigen 19-9 (CA 19-9), and prostate-specific antigen (PSA) in maternal serum (MS), umbilical cord serum (UC), and amniotic fluid (AF) and outlines their roles in the assessment of pregnancy and malignancy. All antigens studied, except CA 15-3, are oncofetal. The presence of considerable concentrations of AFP, hCG, CEA, CA125, SCC, MCA, TPS, CA 19-9, and PSA in AF during pregnancy may be attributed to their involvement in biological functions associated with fetal development, differentiation, and maturation. MS CEA, CA 15-3, and CA 19-9, in contrast to all the others, are not influenced significantly by pregnancy and thus remain reliable tumor markers in monitoring malignancy in pregnant patients.

Carcinoembryonic antigen in high risk pregnancies

The significance of carcinoembryonic antigen (CEA) measurement was evaluated in 25 pregnant women with diabetes mellitus, 15 Rh negative sensitized and nine prolonged pregnancies. Another 114 women with normal pregnancy served as controls. Values in maternal and umbilical cord serum and in amniotic fluid did not change appreciably through 24-42 weeks' gestation. No significant difference in maternal serum, cord serum and amniotic fluid CEA values was found between diabetic, Rh negative sensitized and normal pregnancies at the corresponding weeks. Similar findings were obtained in prolonged pregnancies, except the values in amniotic fluid which were significantly higher than in normal pregnancies due to the presence of meconium. These results suggest that the measurement of CEA in high risk pregnancies is not useful in predicting fetal condition.

Carcinoembryonic antigen (CEA) in normal and pre-eclamptic pregnancies (values in maternal blood, amniotic fluid and umbilical cord blood)

Values of carcinoembryonic antigen (CEA) were measured by radioimmunoassay in 100 pregnant women divided into 4 groups. In group 1 (49 normal pregnancies) and 2 (17 pre-eclamptic pregnancies), the estimation of CEA was done in maternal vein blood, umbilical cord blood and in amniotic fluid. In group 3 (20 normal pregnancies) CEA was measured separately in blood of the two umbilical vessels as well as in maternal vein blood. In group 4 (14 pregnancies with small-for-date infants) CEA was estimated in umbilical cord blood. The values in amniotic fluid of normal and pre-eclamptic pregnancies were more than 20 times higher than in the other two compartments. A significant correlation was found between the amniotic fluid and umbilical cord blood values (r = 0.500; P < 0.05), as well as between the values in umbilical artery and vein (r = 0.792; P < 0.001). Thus, it is thought that CEA is transferred from the amniotic cavity to the umbilical cord while a part of CEA perhaps is produced by the placenta. Umbilical cord blood values of small-for-date fetuses do not differ significantly from the normal. On the contrary, significantly lower values were obtained in umbilical cord blood and in amniotic fluid of pre-eclamptic women as compared to the normal, but this finding is not useful clinically because of the large standard deviation.

Distribution of tumor-associated antigen CEA and cross-reacting NCA in fetal organs

The organ distribution of the tumor-associated carcinoembryonic antigen (CEA), and that of the normal tissue component NCA (non-specific cross-reacting antigen) have been investigated in the fetus. Organ extracts from five fetuses between 14 and 21 weeks of age were analysed by radioimmunoassay using specific antisera. CEA was detected in large amounts (800--1,650 ng/g) in fetal colon and in barely detectable amounts in lung and placental tissue. This differed from NCA, which could be detected in almost all organ extracts analysed. The highest concentration of NCA was measured in fetal colon and the content increased with the gestational age of the fetus. High amounts of NCA were also found in the liver, spleen and placental tissue. The gel elution profiles of CEA and NCA from an amniotic fluid pool and a pool of colonic extracts were also determined. CEA eluted similarly to the marker 125I--CEA purified from liver metastasis of colonic carcinoma. The NCA-reactive material was found in three distinct peaks.