OBJECTIVETo explore the role of Notch signaling in human breast cancers, the expression of Notch1 and its ligand JAG1 in human breast cancers and their relationships with clinical stages of breast cancers were analyzed.

METHODSRT-PCR was used to detect the expression of Notch1 and JAG1 in 62 breast cancer specimens and 22 normal breast tissues at the margin of tumor sections, and the statistical difference of expression rates and standardized coefficient between the two groups were analyzed. To compare the expression intensity of Notch1 and JAG1 at different development stages of the illness and at different stages with or without axillary node metastasis.

RESULTSThe expression rate and standardized coefficient of Notch1 in human breast cancers were significantly higher than those of normal breast tissues at the margin of tumor sections. The expression rate of JAG1 in human breast cancers was 15%, while JAG1 was not detected in normal breast tissues at the margin of tumor sections. The standardized coefficient of Notch1 in cases with axillary node metastasis was significantly higher than that in cases without axillary node metastasis. The standardized coefficient of Notch1 at stage I was significantly lower than that at stage II, and stage II was significantly higher than stage III. There was no statistically significant difference between stage I and stage III.

CONCLUSIONNotch1 and JAG1 are highly expressed in human breast cancers, indicating that the aberrant expression and activation of Notch1 may be related with tumorigenesis of human breast cancer. Notch1 may play different roles at different developmentl stages of human breast cancer.