Abstract: Objective: To explore the expressions of B7-H1 and B7-H4 in colorectal cancer(CRC) tissue and their relationships with the Foxp3⁺ regulated T-cell (Treg) infiltrationin tumor tissue,and to provide the basis for judging the biological behaviours and prognosis of CRC. Methods: Immunohistochemistry was used to detect the expressions of B7-H1 and B7-H4 and the infiltration of Treg in 56 cases of CRC tissue samples and adjacent normal tissue samples,and their relationships with the clinicopathological features of CRC patients were analyzed. Results: The positive expression rate of B7-H1 in CRC tissue of the CRC patients was higher than that in adjacent normal tissue(χ²=72.34,P<0.01).The differences of expression frequencies of B7-H1 in CRC tissues with different infiltration depths were significant (P<0.01). The high expression frequency of B7-H1 in CRC tissue of the patients with positive lymphnode metastasis was higher than that in the patients with negative lymphnode metastasis(P<0.01).The high expression frequency of B7-H1 in CRC tissue of the patients at Duke's stage (C+D) was higher than that of the patients at Duke's stage (A+B)(P<0.01).The positive expression rate of B7-H4 in CRC tissue was higher than that in adjacent normal tissue(χ²=78.92,P<0.01).The differences of expression frequencies of B7-H4 in CRC tissues with different infiltration depths were significant(P<0.05).The high expression frequency of B7-H4 in CRC tissue of the patients with positive lymphnode metastasis was higher than that of the patients with negative lymphnode metastasis(P<0.05).The number of Treg positive expression cells in CRC tissue was significantly higher than that in adjacent normal tissue (P<0.01),the number of Treg postive expression cells in CRC tissues with different differentiation degrees were different(P<0.01),and the number of Treg positive expression cells in CRC tissue of the patients with positive lymphnode metastasis was higher than that of the patients with negative lymph node metastasis(P<0.01).The expression of B7-H1 was correlated with Treg infiltration(P<0.01,Cramer's=0.463);the expression of B7-H4 was correlated with Treg infiltration(P<0.05,Cramer's=0.320). Conclusion: B7-H1 and B7-H4 are highly expressed in human CRC tissue,and they are associated with the increasing of Treg infiltration;they can be used as the indicators to judge the prognosis of CRC.

Key words: regulatory T cells, colorectal neoplasms, B7-H1, B7-H4