Correlation of tumor-associated macrophage density and proportion of M2 subtypes with the pathological stage of colorectal cancer

Table 1 Baseline characteristics

Characteristic	n (%)
Demographics
Age in yr, mean (± SD)	51.02 (16.9)
Sex
Male	30 (69.8)
Female	13 (30.2)
F:M ratio	1:2.3
Specimen details
Procedure
Right hemicolectomy	18 (41.9)
Left hemicolectomy	7 (16.3)
Sigmoidectomy	7 (16.3)
Rectal resection (APR or LAR)	11 (25.5)
Tumor site
Cecum (including ileocecal valve)	11 (25.5)
Right colon (including hepatic flexure)	6 (13.9)
Transverse colon	1 (2.3)
Left colon (including splenic flexure)	3 (7.0)
Sigmoid colon	10 (23.3)
Rectosigmoid	4 (9.3)
Rectum	8 (18.6)
Tumor size, mean (± SD)
Greatest dimension, cm	6.18 (4.8)
Additional dimension, cm	3.9 (2.1)
Pathology
Histologic type
Adenocarcinoma	36 (83.7)
Mucinous adenocarcinoma	6 (14.0)
Signet ring cell adenocarcinoma	1 (2.3)
Histologic grade
G1: well differentiated	21 (48.8)
G2: moderately differentiated	14 (32.5)
G3: poorly differentiated	8 (18.6)
Perforation
Not identified	40 (90.3)
Present	3 (7.0)
Lymphovascular invasion
Not identified	19 (44.2)
Present	24 (55.8)
Perineural invasion
Not identified	34 (79.1)
Present	9 (20.9)
TNM
Primary tumor
pT1	3 (7.0)
pT2	8 (18.6)
pT3	26 (60.5)
pT4	6 (14.0)
Regional lymph nodes
pN0	17 (39.5)
pN1	23 (53.3)
pN2	3 (7.0)
Distant metastasis
pMX	43 (100)
pM1	0 (0)

APR: Abdominoperineal resection; LAR: Low anterior resection; SD: Standard deviation.

Table 2 Tumor-associated macrophage distribution

Population	Tumor stroma	Tumor front	P value1
Densities, median (IQR)
TAM (anti-CD68+)	32 (22-32)	40 (24-53)	0.00031
M2 (anti-CD163+)	21 (15-30)	29 (19-38)	0.00031
M1 (calculated)	7 (4-10)	8 (4-13)	0.0381
Proportion, %
M1	25	29	0.00012
M2	75	71
Ratio, median
M1	9.21 (± 8.98)	10.91 (± 9.36)	0.000013
M2	22.56 (± 9.7)	30 (± 14.86)

¹Wilcoxon signed-rank test of median difference in a nonparametric distribution;

²McNemar test of difference between paired proportions;

³Friedman’s two-way analysis of variance by rank.

TAMs: Tumor-associated macrophages.

Table 3 Logistic regression analysis: Comparison of model 1 and model 2

Model	Observed			Predicted
	Without independent predictors			Stage type		Percentage correct
				Early	Late
Model 1 (TAM density + M2 proportion)	Step 0	Stage type: Early or late	Early	0	17	0
			Late	0	26	100
		Overall percentage				60.5
	Step 1	Stage type: Early or late	Early	6	11	35.31
			Late	6	20	76.92
		Overall percentage				60.53
Model 2 (TAM density + M2 proportion + tumor grade + lymphovascular invasion)	Step 0	Stage type: Early or late	Early	0	17	0
			Late	0	26	100
		Overall percentage				60.5
	Step 1	Stage type: Early or late	Early	13	4	76.51
			Late	4	22	84.62
		Overall percentage				81.43

¹Represents specificity;

²Represents sensitivity;

³Represents overall predictability.

Constant is included in the model. The cutoff value is 500. TAMs: Tumor-associated macrophages.