The human tumor-associated antigen RCAS1 in pregnancies complicated by pre-eclampsia

Breast cancer, placenta and pregnancy

BACKGROUND

Breast cancer is one of the most frequently diagnosed malignancies during pregnancy. Tumours often present characteristics of high malignancy and are hormone receptor negative/HER2 positive or triple negative. In general, pregnancy, including the postpartum period, is associated with a transiently increased risk of developing breast cancer but followed by a long-lasting protective period. Placental metastases are very rare and, thus far, breast cancer metastases in the foetal compartment have not been described. To discuss these apparently contradictory observations, this narrative review resumes immunological and hormonal alterations during pregnancy potentially affecting breast cancer risk as well as tumour growth and behaviour.

OBSERVATIONS

Upregulation of breast cancer-associated genes involved in immunological and reproductive processes has been observed in parous women and is potentially responsible for a transiently increased risk in pregnancy. In contrast, maternal immunisation and immunoglobulin production against antigens expressed on trophoblast cells, such as specific glycosylation patterns of mucin-1 or RCAS1-associated truncated glycans, seem to prevent breast cancer development in later years. Animal and human studies indicate that T cells are involved in these processes. Several placenta-derived factors, especially kisspeptin, have direct anti-tumour effects. The pregnancy-related increase of estrogen, progesterone, and other hormones influence growth and characteristics of breast cancer while the role of further placenta-secreted factors is still controversially discussed.

CONCLUSION

Several factors and cells are involved in altered breast cancer risk during and after pregnancy and have potential for developing novel treatment strategies in future.

Maternal blood serum and plasma human tumor-associated antigen RCAS1 during the course of uncomplicated pregnancies: a prospective study

PROBLEM

we aimed to investigate the expression of the tumor-associated RCAS1 protein in maternal blood of uncomplicated pregnancies.

METHOD OF STUDY

maternal blood was obtained from women with uncomplicated pregnancies (N = 43) at 11-13, 20-22, 32-34, 37-38 weeks of gestation, and immediately after delivery. Serum RCAS1 concentration was studied by ELISA, and plasma mRNA was subjected to real-time (RT)-PCR.

RESULTS

serum RCAS1 protein concentration was significantly up-regulated at 11-13 and 20-22 weeks than that at 32-34 weeks and after delivery. RCAS1 mRNA level was significantly increased at 11-13 weeks than that at 37-38 weeks. A significant positive correlation was defined between RCAS1 serum concentration at 11-13 weeks and gestational age at delivery and that between plasma RCAS1 mRNA levels at 37-38 weeks and umbilical cord blood base excess. A significant negative correlation was found between RCAS1 serum concentration at 37-38 weeks and umbilical cord blood pH at delivery.

CONCLUSIONS

RCAS1 protein might have importance in the development of uncomplicated pregnancies and for the prediction of pregnancy outcome.

The effect of tumor-associated protein RCAS1 gene silencing on blood pressure and urinary protein excretion in pregnant mouse: a pilot study

OBJECTIVE

The level of tumor-associated receptor-binding cancer antigen that is expressed on SiSo cells (RCAS1) is decreased significantly in preeclamptic pregnancies. We hypothesized that RCAS1 protein gene silencing might affect blood pressure and proteinuria in pregnant mice.

STUDY DESIGN

On postcoital day 7.5, pregnant imprinting control region mice were subjected to the transfer of small interfering RNA (siRNA) against RCAS1 protein into the uterine cavity with the use of a hemagglutinating virus Japan envelope. Scramble siRNA was used as a negative control. Blood pressure and urine albumin/creatinine measurements were performed. The effect of the transferred siRNA was examined in uterine samples on postcoital day 8.5 with the use of Western blotting and immunohistochemistry analyses.

RESULTS

In the RCAS1 siRNA group, blood pressure significantly raised on postcoital days 9.5, 10.5, 11.5, and 15.5, whereas urine albumin/creatinine ratio was significantly increased on postcoital day 9.5

CONCLUSION

Our results suggest the importance of RCAS1 protein in the pathophysiologic condition of preeclampsia.