Breast Cancer and Tamoxifen: A Nigerian Perspective to Effective Personalised Therapy

Figures & data

Table 1 Some Keys Factors Mediating the Effectiveness of Tamoxifen in the Management of Hormone-Receptor Positive Breast Cancer

Factors in Tamoxifen Therapy Response	Significance for Tamoxifen Therapy	References
CYP2D6	Metabolism of tamoxifen: Varied drug and metabolite exposure	^Citation21^–^Citation23
BRCA1 and BRCA2mutations	Tamoxifen response: Tamoxifen more effective in non-carriers	^Citation24
Histone deacetylases	Tamoxifen target: Regulatory role in the stability of estrogen receptor mRNA	^Citation25^–^Citation27
Lysine N-methyltransferases (MLL3 and SET1A)	Tamoxifen target: Regulatory methylation of estrogen receptor promoter/enhancer region	^Citation28
Estrogen receptor α gene (ESR1)	Tamoxifen target: Somatic mutations precipitate tamoxifen resistance	^Citation29
SALL2	Tamoxifen target: Mediates estrogen receptor α gene transcription	^Citation30

Table 2 Summary Data of Breast Cancer Patients on Tamoxifen Between 2008 and 2019 in a Tertiary Healthcare Institution in Nigeria

	N = 41
Mean age ± SD (years)	54.1 ± 12.6
Gender
Female	38 (92.7%)
Male	3 (7.3%)
Menopausal status
Premenopausal	18 (43.9%)
Postmenopausal	23 (56.1%)
Stage at diagnosis
II	7 (17%)
III	29 (70.7%)
1V	5 (12.2%)
Nature of therapy
Neoadjuvant	2 (4.9%)
Adjuvant	39 (95.1%)
Duration of therapy
≥5 years	10 (24.4%)
2–3 years	20 (48.8%)
<1 year	11 (26.8%)
Outcome
Alive	35 (85.4%)
Dead	6 (14.6%)
Median duration of follow-up (years)	5

Notes: Data presented was obtained from the registry of the Obafemi Awolowo University Teaching Hospital, Ile-Ife, Nigeria. These patients were diagnosed, treated and followed-up between 2008 and 2019. Contact with one patient was, however, lost after an initial 5-year monitoring of adjuvant tamoxifen.

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