Serum levels of the c-erbB-2 (HER2/neu) encoded oncoprotein fragment p105 in normal pregnancies.

: The c-erbB-2 encoded oncoprotein p185 is overexpressed in fetal epithelial cells, in the placenta, and in several human carcinomas. Elevated serum levels of the 105 kD extracellular part are found in cancer patients and in pregnancy. Our purpose was to examine whether there is a characteristic development of p105 serum levels in the course of normal pregnancy. Using ELISA, we measured the p105 serum concentrations in nonpregnant women, women with normal pregnancy in the 1st, 2nd, and 3rd trimester and pueperas. Compared to nonpregnant women, we found a significant decrease in p105 in the 1st and 2nd trimester, followed by a significant increase in the 3rd trimester. Post partum serum values returned to the levels found in nonpregnant women. The clinical judgment of female p105 serum values requires comparison with the normal range of random samples, and the consideration of pregnancy and the age of gestation as in vivo influencing factors.