Effects of CYP2D6 and UGT2B7 polymorphisms on pharmacokinetics of tamoxifen in Thai breast cancer patients

Figures & data

Table 1 Patient characteristics

Patient characteristic	Mean ± SD (% patients)
Age (years)	50 ± 9.3
Body mass index	22.8 ± 3.8 kg/m^2
Estrogen receptor status
Positive	51 (86.4)
Negative	4 (6.8)
Unknown	4 (6.8)
Progesterone receptor status
Positive	50 (84.7)
Negative	7 (11.9)
Unknown	2 (3.4)
HER-2
Positive	5 (8.5)
Negative	45 (76.3)
Unknown	5 (8.5)
Menopausal status
Pre/peri-menopause	45 (76.3)
Post-menopause	14 (23.7)
TNM stage
T1	24 (40.6)
T2	18 (30.5)
T3	4 (6.8)
T4	3 (5.1)
N0	33 (55.9)
N1	7 (11.9)
N2	9 (15.3)
M0	56 (94.9)
M1	4 (6.8)
Unknown	10 (16.9)

Abbreviations: SD, standard deviation; HER-2, Human Epidermal Growth Factor Receptor 2

Table 2 Genotype frequency of CYP2D6 and UGT2B7

	Allele frequency (%)		Genotype n (%)
CYP2D6	*1	*10	*1/*1	*1/*10	*10/*10
	47	53	16 (27.1)	23 (39)	20 (33.9)
UGT2B7	*1	*2	*1/*1	*1/*2	*2/*2
	72	28	31 (52.5)	23 (39)	5 (8.5)

Table 3 TAM and END concentrations in different CYP2D6 genotypes

Plasma concentration (ng/mL)	CYP2D6*1/*1 (n = 16)	CYP2D6*1/*10 (n = 23)	CYP2D6*10/*10 (n = 20)	P-value
TAMa	323.6 ± 79.8	336.3 ± 151.1	437.3 ± 161.2	0.027*
ENDb	21.55	15.67	9.62	0.045#

Notes:

a Mean

b median (END concentrations were reported as median due to the non-normal distribution of data)

* P-value as ANOVA test

# P-value as Kruskal–Wallis test.

Abbreviations: TAM, tamoxifen; END, endoxifen; ANOVA, analysis of variance.

Table 4 TAM and END concentrations in different UGT2B7 genotypes

Plasma concentration (ng/mL)	UGT2B7*1/*1 (n = 31)	UGT2B7*1/*2 (n = 23)	UGT2B7*2/*2 (n = 5)	P-value
TAMa	362.3 ± 158.8	360.5 ± 130.0	427.3 ± 153.3	0.613
ENDb	14.12	15.33	28.74	0.503

Notes:

a Mean

b median (END concentrations were reported as median due to the non-normal distribution of data).

Abbreviations: TAM, tamoxifen; END, endoxifen.

Table 5 TAM and END concentrations in subgroup of CYP2D6*10/*10 with different UGT2B7 genotypes

Plasma concentration (ng/mL)	UGT2B7*1/*1 (n = 8)	UGT2B7*1/*2 (n = 9)	UGT2B7*2/*2 (n = 3)	P-value
TAMa	395.7 ± 172.8	311.7 ± 95.7	410.8 ± 136.1	0.376
ENDb	9.11	7.86	31.36	0.073#

Notes:

a Mean

b median (END concentrations were reported as median due to the non-normal distribution of data)

# P-value as Kruskal–Wallis test.

Abbreviations: TAM, tamoxifen; END, endoxifen.

Table 6 END concentrations in subgroup of CYP2D6*10/*10 with homozygous and heterozygous UGT2B7*1 versus homozygous UGT2B7*2 genotypes

Plasma concentration (ng/mL)	UGT2B7*1/*1 and UGT2B7*1/*2 (n = 17)	UGT2B7*2/*2 (n = 3)	P-value
TAMa	426.8 ± 164.0	496.8 ± 159.7	0.504
ENDb	7.86	31.36	0.023

Notes:

a Mean

b median (END concentrations were reported as median due to the non-normal distribution of data); P-value as Mann–Whitney U test.

Abbreviations: TAM, tamoxifen; END, endoxifen.