Evaluation of antibody-dependent cell-mediated cytotoxicity activity and cetuximab response in KRAS wild-type metastatic colorectal cancer patients

Table 1 Characteristics of 41 patients in II and III line and tumours

	Number of patients	Rates	Median age (range) yr
Gender
Male (M)	23	56%	67.5 (51-84)
Female (F)	18	44%	64.6 (49-83)
Primary tumour
Right colon	7	17%
Left colon	21	51%
Rectal	13	32%
Grade
G1/G2	27	65.8%
G3	13	31.7%
NA	1	2.5%
Metastasis
Liver only	12	29.3%
Liver plus other sites	14	34.1%
Extra-hepatic sites	15	36.6%
Response
Responders
CR	4	9.8%
PR	12	29.3%
SD	8	19.5%
Non-responders
PD	17	41.4%
Line of treatment
II	33	8%
III	8	2%

NA: Not available; CR: Complete response; PR: Partial response; SD: Stable disease; PD: Progressive disease.

Table 2 FCGR2A (rs1801274; A > G), FCGR3A (rs366991; T > G) and single nucleotide polymorphism rs61764370 of KRAS 3’ untranslated region genotypes with the correspondent aminoacid change in the 41 metastatic colorectal cancer patients included in this study

Gene	SNP	Genotype	Aminoacid change	Number of subjects (%)
FCGR2A	rs1801274	A/A	H131H	14 (34.1%)
		A/G	H131R	20 (48.8%)
		G/G	R131R	7 (17.1%)
FCGR3A	rs396991	T/T	F158F	14 (34.1%)
		T/G	F158V	21 (51.2%)
		G/G	V158V	6 (14.7%)
KRAS 3’ UTR	rs61764370	T/T	---	32 (78%)
		T/G	---	9 (22%)
		G/G	---	0 (0%)

SNP: Single nucleotide polymorphism; UTR: Untranslated region.

Table 3 Comparison of characteristics of 41 patients on the basis of antibody-dependent cell-mediated cytotoxicity activity

	ADCC < 71%	n = 20	ADCC > 71%	n = 21	P
Gender
Male (M)	11	55%	12	57%	0.91
Female (F)	9	45%	9	43%
Primary tumour
Right colon	5	25%	2	10%	0.282
Left colon	8	40%	13	62%
Rectal	7	35%	6	29%
Grade
G1/G2	13	65%	14	67%	0.872
G3	7	35%	6	29%
NA	0	0%	1	5%
Metastasis
Liver only and liver plus other sites	12	60%	14	67%	0.651
Extra-hepatic sites	8	40%	7	33%
Response
Responders
CR	3	15%	1	5%	0.362
PR	4	20%	8	38%
SD	3	15%	5	24%
Non-responders
PD	10	50%	7	33%
Line of treatment
II	17	85%	17	81%	12
III	3	15%	4	19%
EGFR
Neg; 1+; 2+	19	95%	14	67%	0.0522
3+	1	5%	5	24%
NA	0	0%	2	10%

¹Pearson’s Test;

²Fisher’s Exact Test; NA: Not available; Neg: Negative; CR: Complete response; PR: Partial response; SD: Stable disease; PD: Progressive disease; ADCC: Antibody-dependent cell-mediated cytotoxicity; EGFR: Epidermal growth factor receptor.