Basal-Like Subgroup is Associated with Younger Age, Increased Expression of Androgen Receptor, and Worse Prognosis, while Non-basal-like Subtype is Associated with Higher BMI in Triple-Negative Breast Cancer Patients

ACKGROUND: Triple-negative breast cancer
(TNBC) represents a heterogenous disease which
differ in characteristic, treatment response and
prognosis. We aim to perform in-depth analysis on the
clinicopathologic feature and the prognostic value of basallike
and non-basal-like TNBC patients in an Indonesian
tertiary hospital.
METHODS: We retrospectively included patients
diagnosed with TNBC between 2014-2017. Clinical
variables were collected from medical record. Expression
of epidermal growth factor receptor (EGFR), cytokeratin
5/6 (CK5/6), p53 mutant and androgen receptor (AR) were
examined by using immunohistochemistry (IHC).
RESULTS: We included 67 subjects, 67.1% were basal-like
and the remaining 32.9% were non-basal-like, with mean
age of 51 years old, 59.7% subjects had BMI <25 and 40.3%
subjects had BMI ≥25; 16.4%, 65.7%, and 17.9% subjects
presented with early stage, locally advanced stage, and
distant metastasis respectively; T<5 cm was found in 29.9%
subjects, while 70.1% subjects had T≥5; 67.2% subjects
presented with N-, while 32.8% subjects were N+. The most
common histological type was infiltrating ductal (82% of
subjects). P53 mutant and AR expressions were positive in
44.8% and 15% subjects, respectively. Basal-like subtype
presented with younger age at and had higher expression
of AR, while non-basal-like subtype is associated with
BMI ≥25 (p<0.05). Basal-like subjects had shorter overall
survival (23.9 months (95% CI: 21.9-25.9) vs. 26.1 months
(95% CI: 23-29.2).
CONCLUSION: Basal-like subtype is associated with
worse prognosis, younger age at diagnosis and increased
expression of AR, while non-basal-like subtype is associated
with higher BMI in Indonesian TNBC.