Expression of APOBEC3B mRNA in Primary Breast Cancer of Japanese Women

Abstract

Recent studies have identified the apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3B (APOBEC3B) as a source of mutations in various malignancies. APOBEC3B is overexpressed in several human cancer types, including breast cancer. In this study, we analyzed APOBEC3B mRNA expression in 305 primary breast cancers of Japanese women using quantitative reverse transcription-PCR, and investigated the relationships between the APOBEC3B mRNA expression and clinicopathological characteristics, prognosis, and TP53 mutations. The expression of APOBEC3B mRNA was detected in 277 tumors and not detected in 28 tumors. High APOBEC3B mRNA expression was significantly correlated with ER- and PR-negativity, high grade and high Ki67 index. The APOBEC3B mRNA expression was highest in the triple-negative and lowest in the hormone receptor-positive/HER2-negative subtypes. The TP53 gene was more frequently mutated in the tumors with high APOBEC3B mRNA expression. High APOBEC3B mRNA expression was significantly associated with poor recurrence-free survival in all cases and the ER-positive cases. These findings were almost consistent with the previous reports from the Western countries. In conclusion, high APOBEC3B mRNA expression was related to the aggressive phenotypes of breast cancer, high frequency of TP53 mutation and poor prognosis, especially in ER-positive tumors.

GATA3 and APOBEC3B are prognostic markers in adrenocortical carcinoma and APOBEC3B is directly transcriptionally regulated by GATA3

“…In our study, the higher levels of γ-H2AX were detected in ACC as compared to normal adrenal cortices and benign adrenocortical tumors with partial co-localization within the nucleus of APOBEC3B. The TP53 gene is frequently mutated in many cancers and tumors with TP53 mutations have also been reported to have higher levels of APOBEC3B expression in breast cancer [26] and ovarian cancers [12]. Our results show that APOBEC3B expression level is associated with a higher rate of TP53 mutations in ACC [12,18].…”

“…The TP53 gene is frequently mutated in many cancers and tumors with TP53 mutations have also been reported to have higher levels of APOBEC3B expression in breast cancer [ 26 ] and ovarian cancers [ 12 ]. Our results show that APOBEC3B expression level is associated with a higher rate of TP53 mutations in ACC [ 12 , 18 ].…”

APOBEC3B gene expression as a novel predictive factor for pathological complete response to neoadjuvant chemotherapy in breast cancer

“…These parameters are progressive factors, and this result is consistent with previous studies showing high APOBEC3B mRNA expression in many progressive cases. Previous studies have shown that high APOBEC3B mRNA expression was associated with poor prognosis [ 21 - 25 , 49 , 50 ]. In particular, it was reported that high APOBEC3BmRNA expression was an independent prognostic factor for ER+ and lymph node-negative cases [ 21 , 23 , 25 ].…”

“…Previous studies have shown that high APOBEC3B mRNA expression was associated with poor prognosis [ 21 - 25 , 49 , 50 ]. In particular, it was reported that high APOBEC3BmRNA expression was an independent prognostic factor for ER+ and lymph node-negative cases [ 21 , 23 , 25 ]. However, our study could not reveal the association between APOBEC3B mRNA expression levels and prognosis, in part because of the difference in patient population among trials.…”

“…High expression of APOBEC3B has been reported in advanced cases and cases with poor prognosis [ 10 , 23 ]. Recently, it has also been shown that APOBEC3B influences metastasization, prognosis and endocrine therapy resistance in estrogen receptor (ER) -positive breast cancer [ 22 – 25 ].…”