Clinical value of detecting IQGAP3, B7-H4 and cyclooxygenase-2 in the diagnosis and prognostic evaluation of colorectal cancer

Abstract

Background: The IQ-motif-containing GTPase-activating protein (IQGAP) family comprises three members, IQGAP1, IQGAP2 and IQGAP3. IQGAP3 is the latest addition to the family. This study mainly investigated the novel marker IQGAP3 at serum and tumor tissue levels compared with the markers B7-H4 and cyclooxygenase-2 (COX-2) in patients with colorectal cancer (CRC) and in healthy individuals, aiming to evaluate the diagnostic and prognostic value of IQGAP3 for CRC.

Materials and methods: Serum samples were collected prior to any therapy in 118 CRC patients and as part of a routine examination in 85 healthy individuals. Serum IQGAP3, B7-H4 and COX-2 levels were measured using commercially available ELISA kits. Immunohistochemistry was performed to detect the IQGAP3, B7-H4 and COX-2 in tumor tissues and normal para-carcinoma tissues. The receiver operating characteristics (ROC) curve and the area under the curve (AUC) were used to evaluate and compare the diagnostic value of different serum tumor markers. Univariate and multivariate analyses were performed to identify the prognostic risk factors for CRC.

Results: IQGAP3, B7-H4 and COX-2 showed low or high expression in tumor tissues while no expression in normal para-carcinoma tissues. Serum levels of IQGAP3 in CRC group were significantly higher than those in healthy control group (P < 0.001). The IQGAP3 AUC was 0.799, while the B7-H4 AUC was 0.795 and the COX-2 AUC was 0.796. IQGAP3 seemed to be superior to B7-H4 and COX-2 in detecting CRC, with the highest sensitivity among the three markers. Multivariate analysis showed that T stage, N stage, differentiation degree, TNM stage and both serum and tissue IQGAP3, B7-H4 and COX-2 levels were significant prognostic factors for CRC.

Conclusions: IQGAP3 has a better diagnostic efficacy than B7-H4 and COX-2 in detecting CRC and it has value in predicting the prognosis of patients with CRC.

Keywords: B7-H4; Colorectal cancer; Cyclooxygenase-2; Diagnostic markers; IQ-motif-containing GTPase-activating protein; IQGAP3.

Fig. 1

Levels of tissue tumor markers in different group. 118 CRC patients from May 2011 to May 2013 and 62 CRC patients from January 2018 to January 2019 were analyzed. Specimens were subjected to routine deparaffinization and rehydration. The original anti-IQGAP3 antibody, anti-B7-H4 antibody and anti-COX-2 antibody were used in a 1:200 dilution. Immunohistochemical expression of IQGAP3, B7-H4 and COX-2 in tumor tissues and normal para-carcinoma tissues was observed in the cytoplasm with different intensities. Positive staining showed a brown color. Low expression of immunohistochemical staining of three molecules in a IQGAP3, b B7-H4, c COX-2, respectively (×400), with expression quantity of 20%, 10%, 10%, respectively. High expression of immunohistochemical staining of three molecules in d IQGAP3, e B7-H4, f COX-2, respectively (×400), with expression quantity of 70%, 80%, 80%, respectively. Negative immunohistochemical staining of normal para-carcinoma tissues in g IQGAP3, h B7-H4, and i COX-2, respectively (×100), with expression quantity of zero in all

Fig. 2

Correlations between serum tumor markers. 118 CRC patients from May 2011 to May 2013 were analyzed. a There was a correlation between IQGAP3 and B7-H4 levels (r = 0.710, P < 0.001). Points show IQGAP3 or B7-H4 levels of each patient, with X axis indicating B7-H4 levels (ng/ml) and Y axis indicating IQGAP3 levels (pg/ml). b There was a correlation between IQGAP3 and COX-2 levels (r = 0.860, P < 0.001). Points show IQGAP3 or COX-2 levels of each patient, with X axis indicating COX-2 levels (ng/ml) and Y axis indicating IQGAP3 levels (pg/ml). c There was a correlation between B7-H4 and COX-2 levels (r = 0.724, P < 0.001). Points show B7-H4 or COX-2 levels of each patient, with X axis indicating COX-2 levels (ng/ml) and Y axis indicating B7-H4 levels (ng/ml)

Fig. 3

ROC curves of tumor markers in CRC patients. 118 CRC patients from May 2011 to May 2013 were analyzed. a The IQGAP3 AUC was 0.799, with 95% Confidence interval (CI) 0.736–0.861 (P < 0.001). b The B7-H4 AUC was 0.795 (95% CI 0.731–0.858, P < 0.001). c The COX-2 AUC was 0.796 (95% CI 0.737–0.856, P < 0.001). d The IQGAP3 + B7-H4 AUC was 0.876 (95% CI 0.825–0.927, P < 0.001). e The IQGAP3 + COX-2 AUC was 0.889 (95% CI 0.842–0.936, P < 0.001). f The B7-H4 + COX-2 AUC was 0.875 (95% CI 0.827–0.924, P < 0.001). g The AUC of IQGAP3 + B7-H4 + COX-2 was 0.926 (95% CI 0.887–0.966, P < 0.001). h The CEA AUC was 0.786, (95% CI 0.725–0.847, P < 0.001). i The CA19-9 AUC was 0.777, (95% CI 0.714–0.840, P < 0.001)

Fig. 4

Overall survival rates for patients in different groups. 118 CRC patients from May 2011 to May 2013 were analyzed. We divided patients into several subgroups according to tumor marker levels, T stage, N stage and TNM stage. a The 5-year survival rates in s-IQGAP3 low group were significantly higher than those in s-IQGAP3 high group (s-IQGAP3 low 85.7% vs. s-IQGAP3 high 48.1%, P = 0.007). b The 5-year survival rates in s-B7-H4 low group were significantly higher than those in s-B7-H4 high group (s-B7-H4 low 78.6% vs. s-B7-H4 high 49.0%, P = 0.015). c The 5-year survival rates in s-COX-2 low group were significantly higher than those in s-COX-2 high group (s-COX-2 low 73.8% vs. s-COX-2 high 40.8%, P < 0.001). d The 5-year survival rates in t-IQGAP3 low group were significantly higher than those in t-IQGAP3 high group (t-IQGAP3 low 65.6% vs. t-IQGAP3 high 38.6%, P < 0.001). e The 5-year survival rates in t-B7-H4 low group were significantly higher than those in t-B7-H4 high group (t-B7-H4 low 73.1% vs. t-B7-H4 high 36.4%, P < 0.001). f The 5-year survival rates in t-COX-2 low group were significantly higher than those in t-COX-2 high group (t-COX-2 low 67.3% vs. t-COX-2 high 39.7%, P < 0.001). g The 5-year survival rates in the four T stages were significantly different (T1 77.3% vs. T2 59.4% vs. T3 47.1% vs. T4 33.3%). h The 5-year survival rates in the three N stages were significantly different (N0 68.8% vs. N1 48.7% vs. N2 32.3%). i The 5-year survival rates in the three TNM stages were significantly different (stage I 80.0% vs. stage II 60.7% vs. stage III 41.4%)