The present study aimed to evaluate the expression of human
epidermal growth factor receptor (HER4)
isoforms and their
ligand neuregulin 1 (NRG1)
isoforms in human primary
colorectal cancer (CRC). The
mRNA expression of HER4
isoforms JM-a, JM-b, CYT1 and CYT2, and their
ligand isoforms NRG1 I, II and III in CRC tissues and adjacent normal tissues were quantified by reverse transcription-quantitative polymerase chain reaction analysis. Univariate analysis and logistic regression analysis were performed to analyze the association between HER4 and NRG1 expression and
lymph node metastasis in CRC. The expression levels of CYT1 (P=0.002), CYT2 (P=0.002) and NRG1 type III (P<0.001) were significantly higher in the CRC tissues than in the adjacent normal tissues. The expression of CYT2 was correlated with
tumor stage (P=0.018), lymph node status (P=0.015) and
tumor-node-
metastasis (P=0.038) in CRC. The expression of NRG1III was correlated with
lymph node metastasis, and the expression of CYT2 was associated with the expression of NRG1III (r=0.691, P<0.01). The logistic regression analysis indicated that expression of CYT2 >50 was a risk factor for
lymph node metastasis in CRC. In conclusion the expression levels of CYT1, CYT2 and NRG1III were upregulated in CRC. An expression of CYT-2 >50 was identified as a risk factor for
lymph node metastasis in CRC. Therefore, CY-2 and NRG1III may be involved in the progression of CRC.