Abstract: Objective  To discuss the expression level of Transcobalamin I(TCN1) in colorectal cancer(CRC) and lung metastasis tumors and its clinical significance.
Methods  A total of 42 cases of CRC patients with lung metastasis were collected in the Fourth Hospital of Hebei Medical University form May,2009 to January,2019.The expression level of TCN1 in the tissues,including CRC tissues,adjacent normal colonrectal mucosa tissues,lung metastastatic tissues and normal lung tissues,was detected by immunohistochemistry(IHC),and the relationships between expression level of TCN1 and the clinical characteristics of CRC were analyzed.
Results  TCN1 was highly expressed in CRC and its lung metastasis tissues than in the adjacent colorectal mucosa and normal lung tissues(P<0.01).There was a similar expression levels between the expression level of TCN1  in CRC and its lung metastasis tissues and CRC and normal lung tissues(P=0.588).The expression level of TCN1 in CRC tissues by colonoscopy was consistent with that in surgically resected CRC tissues(P<0.01).TCN1 expression level in CRC tissue decreased after neoadjuvant chemotherapy.
Conclusion  TCN1 is highly expressed in CRC and CRC lung metastasis tissues,neoadjuvant chemotherapy can reduce the expression level of TCN1 in CRC tissues.TCN1 is expected to be a biomarker for predicting lung metastasis and chemosensitivity of CRC.

Key words: transcobalamin 1, colonrectal cancer, metastatic tumor of lung, neoadjuvant chemotherapy