Association of CD66b + neutrophils with survival
In total, 612 patients were enrolled in the study. In the training cohort by IHC, based on the cutoff value of 66 in neutrophils (Fig. 1A and 1B), Then patients with high and low neutrophils infiltration were identified for further analysis (< 66 as low neutrophils infiltration group and > 66 as high infiltration group). Patients with high number of CD66b + neutrophils had a significantly worse DSS than those with low number of CD66b + neutrophils (P < 0.05, Fig. 1D). A tendency of worse DFS was found to be associated with high number of CD66b + neutrophils,in spite of no statistical significance (P = 0.68, Fig. 1C). Not only CD66b + cells, but also CD3+, CD8+, and FOXP3 + cells were observed in gastric cancer tissues. The ability of neutrophils expressing CD66b to regulate the immune-cell infiltration may account for this survival profit. To investigate the relationship of neutrophils and immune and inflammatory cells, the relationships of CD66b with CD3, CD8, and FOXP3 expression were assessed. The pattern of CD66b expression was negatively correlated with CD8 (r2 = 0.386, P < 0.001, Fig. 2A), and negatively correlated with FOXP3 (r2 = 0.367, P < 0.001, Fig. 2B). No significant correlation of CD66b with CD3 (P > 0.05) was seen.
In the validation cohort, based on the cutoff value of 66 in neutrophils, Then patients with high and low neutrophils infiltration were identified for further analysis (< 66 as low neutrophils infiltration group and > 66 as high neutrophils infiltration group). Kaplan-Meier analysis also showed that high neutrophils were associated with worse DFS of GC patients (P = 0.020, Figure E). A tendency of worse DSS was found to be associated with high number of CD66b + neutrophils,in spite of no statistical significance (P = 0.74, Fig. 1F). To validate the relationship of neutrophils and immune and inflammatory cells, the distributions of positively labeled cells with CD66b, CD3, CD8, and FOXP3 were assessed. The number of neutrophils expressing CD66b was negatively correlated with CD8 cells (r2 = 0.383, P < 0.001, Supplementary Fig. 1A), and negatively correlated with FOXP3 (r2 = 0.569, P < 0.001, Supplementary Fig. 1B). No significant correlation of CD66b with CD3 (P > 0.05) was seen.
To validate the result that neutrophils was negatively linked with CD8 + cells and Treg cells in cancer tissue, multi-color immunofluorescence was performed using antibodies recognizing CD66b, CD8, FOXP3 and DAPI. The number of CD8 + cells was significantly higher in tumors, when CD66b expression decreased (Fig. 2C). When CD66b expression increased, the number of CD8 cells was significantly lower (Fig. 2D). In addition, the number of FOXP3 + cells was significantly higher in tumors, when CD66b expression decreased (Fig. 2E). When CD66b expression increased, the number of FOXP3 + cells was significantly lower (Fig. 2F).
Risk Stratification Based On Cd66b + neutrophils And T Immune Cells
To illustrate the correlation of tumor-infiltration immune and inflammatory cells with clinicopathological factors and prognosis, we developed a risk signature model prediction survival based on neutrophils and immune cells. We divided the patients into high-risk and low-risk groups based on the four immune cells with an NTP algorithm to assess the prognostic impact of immune profile in GC patients. What is more, we transposed the risk signature into a predictive score to make the model easier to use in further study. The high-score group determined by predictive score > 2 had been identified as the high-risk group, and the low-risk group with the score ≤ 2 (Table 1and Supplementary Tables 1).
In the training cohort, patients in the high-risk group had worse survival of DFS and DSS than those in the low-risk group (P < 0.001 and P < 0.001, Fig. 3A and Fig. 3B). In addition, Kaplan-Meier analysis also showed that the high-risk group was associated with worse DFS and DSS of GC patients (P < 0.001 and P < 0.001, Fig. 3C and 3D) in the validation cohort.
Risk Stratification with CD66b + TANs and T immune cells is an independent
Predictor Of Dfs And Dss
Univariate and multivariate analyses for DFS and DSS were carried out (Tables 2 and Tables 3). Univariate analysis of the training cohort for DFS revealed that age, tumor location, tumor size, TNM stage, Lauren classification, lymphovascular invasion, risk signature and postoperative adjuvant chemotherapy were significantly associated with poor DFS (all P < 0.05) (Tables 2). Multivariate analysis of the training cohort balancing those factors showed that TNM stage, postoperative adjuvant chemotherapy and high-risk signature (HR 2.777; 95% CI 1.945–3.966; p < 0.001) were independent predictors of poor DFS (Tables 2). Regarding disease-special survival, univariate analysis of the training cohort found that age, tumor location, tumor size, TNM stage, Lauren classification, tumor differentiation, lymphovascular invasion, perineural invasion, risk signature and postoperative adjuvant chemotherapy were significantly associated with poor DSS (Tables 3). Tumor size, TNM stage, postoperative adjuvant chemotherapy and high-risk signature (HR3.233; 95% CI 2.247–4.651; p < 0.001) were independent predictors of poor DFS in multivariate analysis (Tables 3).
Table 1
The clinicopathologic and treatment-related characteristics of the patients
Variables | Inflammation risk signature | p value |
| Low risk (n = 213) | High risk (n = 114) | |
Gender | | | 0.450 |
Male | 156 | 79 | |
Female | 57 | 35 | |
Age | | | 0.916 |
≤70 | 184 | 98 | |
>70 | 29 | 16 | |
ASA score | | | 0.945 |
I | 49 | 28 | |
II | 148 | 78 | |
III | 16 | 8 | |
BMI(kg/m2) | 21.433 ± 3.437 | 21.796 ± 3.263 | 0.301 |
Tumor location | | | 0.814 |
Upper third | 65 | 31 | |
Middle third | 70 | 40 | |
Lower third | 78 | 43 | |
Tumor size | | | 0.662 |
≤ 5.0 | 136 | 70 | |
> 5 | 77 | 44 | |
TNM stage | | | 0.031 |
I | 32 | 24 | |
II | 52 | 35 | |
III | 97 | 49 | |
Ⅳ | 32 | 6 | |
Lauren classification | | | 0.081 |
Intestinal | 154 | 81 | |
Diffuse | 32 | 10 | |
Mixed | 27 | 23 | |
Tumor differentiation | | | 0.113 |
G1/ G2 | 78 | 52 | |
G3/signet ring cell/mucinous | 135 | 62 | |
Lymphovascular invasion | | | 0.958 |
No | 147 | 66 | |
Yes | 79 | 35 | |
Perineural invasion | | | 0.951 |
No | 102 | 55 | |
Yes | 111 | 59 | |
Fua | | | 0.002 |
Yes | 99 | 90 | |
No | 72 | 29 | |
ECOG: Eastern Cooperative Group Performance Status; ASA: The American Society of Anesthesiologists; BMI: body mass index |
Table 2
Univariate and multivariate analysis for DFS.
| HR (95% CI) | P value | | HR (95% CI) | P value |
Gender | | 0.555 | | | |
Male | 1 | | | | |
Female | 0.911(0.669–1.241) | | | | |
Age | | 0.003 | | | 0.193 |
≤70 | 1 | | | 1 | |
>70 | 1.688(1.185–2.403) | | | 1.295(0.878–1.911) | |
ASA score | | 0.284 | | | |
I | 1 | | | | |
II | 1.301(0.920–1.841) | | | | |
III | 1.407(0.799–2.478) | | | | |
Tumor location | | < 0.001 | | | 0.183 |
Upper third | 1 | | | 1 | |
Middle third | 0.916(0.661–1.269) | | | 1.340(0.931–1.927) | |
Lower third | 0.544(0.384–0.771) | | | 0.995(0.669–1.481) | |
Tumor size | | < 0.001 | | | 0.129 |
≤ 5.0 | 1 | | | 1 | |
> 5 | 2.246(1.702–2.963) | | | 1.287(0.929–1.783) | |
TNM stage | | < 0.001 | | | < 0.001 |
I | 1 | | | 1 | |
II | 1.965(1.104–3.498) | | | 0.977(0.483–1.976) | |
III | 4.503(2.662–7.619) | | | 2.625(1.334–5.165) | |
Ⅳ | 8.372(4.591–15.267) | | | 4.632(2.157–9.947) | |
Lauren classification | | 0.015 | | | 0.178 |
Intestinal | 1 | | | 1 | |
Diffuse | 1.703(1.158–2.503) | | | 1.334(0.892–1.996) | |
Mixed | 1.325(0.910–1.928) | | | 1.352(0.912–2.004) | |
Tumor differentiation | | 0.308 | | | |
G1/ G2 | 1 | | | | |
G3/signet ring cell/mucinous | 1.159(0.873–1.538) | | | | |
Lymphovascular invasion | | 0.031 | | | 0.684 |
No | 1 | | | 1 | |
Yes | 1.374(1.029–1.835) | | | 1.076(0.755–1.534) | |
Perineural invasion | | 0.060 | | | |
No | 1 | | | | |
Yes | 1.301(0.988–1.714) | | | | |
Risk signature | | < 0.001 | | | < 0.001 |
Low | 1 | | | 1 | |
High | 2.681(1.930–3.723) | | | 2.777(1.945–3.966) | |
Fua | | < 0.001 | | | 0.001 |
Yes | 1 | | | 1 | |
No | 1.695(1.281–2.242) | | | 1.713(1.256–2.338) | |
ECOG: Eastern Cooperative Group Performance Status; ASA: The American Society of Anesthesiologists; BMI: body mass index |
Table 3
Univariate and multivariate analysis for DSS.
| HR (95% CI) | P value | | HR (95% CI) | P value |
Gender | | 0.342 | | | |
Male | 1 | | | | |
Female | 0.849(0.606–1.190) | | | | |
Age | | 0.001 | | | 0.105 |
≤70 | 1 | | | 1 | |
>70 | 1.861(1.289–2.686) | | | 1.388(0.934–2.064) | |
ASA score | | 0.196 | | | |
I | 1 | | | | |
II | 1.304(0.911–1.868) | | | | |
III | 1.614(0.910–2.862) | | | | |
Tumor location | | 0.003 | | | 0.174 |
Upper third | 1 | | | 1 | |
Middle third | 0.930(0.666-1.300) | | | 1.425(0.983–2.066) | |
Lower third | 0.567(0.397–0.811) | | | 1.209(0.805–1.816) | |
Tumor size | | < 0.001 | | | 0.013 |
≤ 5.0 | 1 | | | 1 | |
> 5 | 2.532(1.906–3.364) | | | 1.519 (1.092–2.113) | |
TNM stage | | < 0.001 | | | < 0.001 |
I | 1 | | | 1 | |
II | 2.285(1.221–4.276) | | | 1.128(0.536–2.371) | |
III | 5.223(2.938–9.321) | | | 3.020(1.480–6.164) | |
Ⅳ | 10.219(5.366–19.462) | | | 5.668(2.556–12.570) | |
Lauren classification | | 0.012 | | | 0.075 |
Intestinal | 1 | | | 1 | |
Diffuse | 1.698(1.147–2.514) | | | 1.367(0.908–2.057) | |
Mixed | 1.417(0.966–2.078) | | | 1.439(0.964–2.146) | |
Tumor differentiation | | 0.159 | | | |
G1/ G2 | 1 | | | | |
G3/signet ring cell/mucinous | 1.232(0.921–1.649) | | | | |
Lymphovascular invasion | | 0.008 | | | 0.481 |
No | 1 | | | 1 | |
Yes | 1.487(1.108-1. 995) | | | 1.133(0.800-1.604) | |
Perineural invasion | | 0.009 | | | 0.282 |
No | 1 | | | 1 | |
Yes | 1.454(1.095–1.930) | | | 1.155(0.836–1.596) | |
Risk signature | | < 0.001 | | | < 0.001 |
Low | 1 | | | 1 | |
High | 2.862(2.040–4.015) | | | 3.233(2.247–4.651) | |
Fua | | < 0.001 | | | < 0.001 |
Yes | 1 | | | 1 | |
No | 1.818(1.367–2.412) | | | 1.844(1.342–2.534) | |
ECOG: Eastern Cooperative Group Performance Status; ASA: The American Society of Anesthesiologists; BMI: body mass index |
Univariate analysis of the validation cohort for DFS revealed that tumor location, tumor size, TNM stage, Lauren classification, lymphovascular invasion, perineural invasion, risk signature and postoperative adjuvant chemotherapy were significantly associated with poor DFS (Supplementary Tables 2). Multivariate analysis of the validation cohort balancing those factors showed that tumor size, TNM stage, postoperative adjuvant chemotherapy and high-risk signature (HR2.126; 95% CI 1.463–3.090; p < 0.001) were independent predictors of poor DFS (Supplementary Tables 2). Regarding disease-special survival, univariate analysis of the validation cohort found that tumor location, tumor size, TNM stage, Lauren classification, lymphovascular invasion, perineural invasion, risk signature and postoperative adjuvant chemotherapy were significantly associated with poor DSS (Supplementary Tables 3). Tumor size, TNM stage, postoperative adjuvant chemotherapy and high-risk signature (HR1.986; 95% CI 1.372–2.874; p < 0.001) were independent predictors of poor DSS in multivariate analysis (Supplementary Tables 3).
Risk Stratification of CD66b + TAN and T immune cells is correlated with distant metastases
To address why a high-risk signature had a correlation with poor prognosis, relapse patterns were deeply determined. All patients with relapse could be properly assessed for this analysis. Relapse involving anastomosis and pelvic lymph nodes were defined as local. Relapse involving organs such as the liver, lungs, peritoneum, and retroperitoneal nodes were defined as distant. Relapse involving serum tumor markers (including CEA and CA199) also indicate recurrence. In the training cohort, the high-risk signature was found to correlate with local and distant recurrence significantly (Fig. 4C). CEA levels and CA199, two of the most widely used tumor markers for detection recurrence in GC, were included in this comparative analysis. A significantly greater increase in CEA and CA199 was observed in the high-risk signature group than that in the low-risk signature group (Fig. 4A and 4B). In the validation cohort, the high-risk signature was found to correlate with local and distant recurrence significantly (Fig. 4F). A significantly greater increase in CEA and CA199 was also observed in the high-risk signature group than that in the low-risk signature group (Fig. 4D and 4E).
Extension of the distant metastases prognostic model with risk signature
To improve the prognostic accuracy for current TNM staging system, we developed a predictive model for GC patients by combining TNM stage and this risk signature with neutrophils plus T immune cells. In the training cohort, the area under the curve (AUC) as prediction based on the TNM staging (0.703) was comparable with that for the risk signature with neutrophils plus T immune cells (0.657), and the combination of both factors achieved the highest AUC value (0.782) (Fig. 4G). In the validation cohort, the area under the curve (AUC) as prediction based on the T staging (0.727) was comparable with that for the risk signature with neutrophils plus T immune cells (0.614), and the combination of both factors achieved the highest AUC value (0.768) (Fig. 4H).
Predictive Value Of Risk Signature For Adjuvant Chemotherapy Benefit
Increased levels of immune and inflammation cells have been reported to promote tumor invasion and reduce chemotherapy efficacy and immunologic death. Thus, we evaluated the benefit of fluorouracil-based adjuvant chemotherapy according to the risk signature model of neutrophils plus T immune cells. In the training cohort, patients who received postoperative chemotherapy had better DFS and DSS (Supplementary Fig. 2A and 2B, p < 0.001 and p < 0.001, respectively). Similar results were obtained from the training cohort (Supplementary Fig. 2C and 2D, p < 0.001 and p < 0.001, respectively).
In addition, high risk signature patients was not associated with a better DFS and DSS in patients with postoperative adjuvant chemotherapy (Fig. 5A and 5B, HR 1.248; 95% CI 0.909–1.715; p = 0.171, HR 1.348; 95% CI 0.976–1.863; p = 0.069, respectively). The result of validation cohort further conformed that patients with high risk signature patients did not have improved DFS and DSS with postoperative adjuvant chemotherapy (Fig. 5C and D, HR 1.273; 95% CI 0.876–1.848; p = 0.204, HR 1.353; 95% CI 0.932–1.964; p = 0.111, respectively). In contrast, low risk signature patients was associated with reduced risk of DFS and DSS in patients who received postoperative adjuvant chemotherapy (Fig. 5E and 5F, p = 0.004 and p = 0.002, respectively). Low risk signature patients was also associated with reduced risk of DFS and DSS in the validation cohort (Fig. 5G and 5H, p = 0.003 and p = 0.005, respectively).