Abstract P4-08-07: PIK3CA mutation, reduced AKT serine 473 phosphorylation, and increased ERα serine 167 phosphorylation are positive prognostic indicators in postmenopausal estrogen receptor-positive, HER2-negative early breast cancer

Background: Endocrine therapy is the most important treatment option for women with estrogen receptor (ER)-positive breast cancer. We recently reported that approximately two-thirds of patients who relapsed within 5 years had received anthracyclins and/or taxanes as adjuvant or neoadjuvant chemotherapy in addition to adjuvant endocrine therapy. New strategies, such as signal transduction inhibitors together with endocrine therapy are required to improve survival. PIK3CA mutations are detected in almost 40% of early ER-positive breast cancers, and are therefore the most frequent genetic alterations in this subtype. PIK3CA mutation status is reported to affect activation of AKT and ERα. Moreover, recent studies demonstrate that patients had a better prognosis when tumors expressed ER, androgen receptor (AR), and vitamin D receptor (VDR).

Methods: Expression of AR and VDR, phosphorylation of AKT serine (Ser) 473 (AKT phospho-Ser473) and ERα Ser167 (ERα phospho-Ser167) were examined by immunohistochemistry in ER-positive, HER2-negative early breast cancer tissues. Seventeen mutations in exons 1, 4, 7, 9, and 20 of the PIK3CA gene were detected in genomic DNA extracted from formalin-fixed paraffin-embedded tumor blocks. Correlations between these biological markers and clinicopathological factors and prognosis were analyzed separately in pre- and postmenopausal women.

Results: Levels of AKT phospho-Ser473 were significantly higher in premenopausal women (n = 62) than in postmenopausal women (n = 152) (P < 0.0001 and P = 0.014, respectively). In contrast, expression levels of AR were significantly higher in postmenopausal women than in premenopausal women (P < 0.0001). In premenopausal women, 26 tumors (43%) had a single mutation of PIK3CA gene, and 3 tumors (5%) had mutations at two sites. In postmenopausal women, 64 tumors (44%) had a single PIK3CA mutation, 6 tumors (4%) had mutations at two sites, and one tumor (1%) had mutations at three sites. In premenopausal women, wild type PIK3CA was associated with smaller tumor size, higher ER expression levels, and lower AR expression levels when compared with women in the same cohort with PIK3CA mutant tumors. In postmenopausal women, patients with PIK3CA wild-type tumors had higher Ki67 labeling index, higher AKT phospho-Ser473, and lower ERα phospho-Ser167 when compared to patients with PIK3CA mutant tumors. Postmenopausal women with PIK3CA wild-type tumors had significantly worse disease-free survival than patients with PIK3CA mutant tumors (P = 0.007). In contrast, PIK3CA mutation status was not correlated with survival in premenopausal women. Low levels of AKT phospho-Ser473 and high levels of ERα phospho-Ser167 were strongly associated with increased disease-free survival in postmenopausal women (P = 0.016 and P = 0.0016, respectively).

Conclusion: ERα activation, in addition to PIK3CA mutation, may be biomarkers for highly endocrine-responsive tumors. This would facilitate the selection of postmenopausal ER-positive breast cancer patients who are likely to benefit from endocrine therapy alone from those who are not.

Citation Format: Ishida N, Hatanaka Y, Baba M, Hagio K, Okada H, Hatanaka KC, Matsuno Y, Yamashita H. PIK3CA mutation, reduced AKT serine 473 phosphorylation, and increased ERα serine 167 phosphorylation are positive prognostic indicators in postmenopausal estrogen receptor-positive, HER2-negative early breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-08-07.

Abstract P5-08-15: Prognostic value of aldehyde dehydrogenase 1 (ALDH1) and tumor infiltrating lymphocytes (TIL) to predict the late recurrence in ER positive, HER2 negative breast cancer

Introduction: Aldehyde dehydrogenase 1(ALDH1) is known to be cancer stem cell marker. Also, tumor infiltrating lymphocytes (TILs) are known to be prognostic factor for triple negative breast cancer. It is reported that these factors have the correlation with chemosensitivity. Meanwhile, the late recurrence (LRec; 5 years after primary surgery) of ER positive breast cancer is the major problem. Significance of expressions of ALDH1 and TILs in primary tumor as predictive factors for late recurrence in ER positive, HER2 negative breast cancer is still unknown.

Methods: ER-positive, and HER2-negative breast cancer patients who underwent surgery or received neoadjuvant chemotherapy between January 2000 and December 2004 were registered from nine institutes belonging the Collaborative Study Group of Scientific Research of the Japanese Breast Cancer Society. For each LRec patient, approximately two matched control patients without relapse for more than ten years were selected. Expression of ALDH1 was assessed by immunohistochemistry. Positive ALDH1 was defined as tumor including more than 1% cancer cells with ALDH1 expression. TIL was assessed by single whole section according to Denkert's definition. A tumor showing high ki67 and/or low PgR expressions was categorized into Luminal B-like group.

Results: 639 patients (184 with early recurrence (ERec), 134 with LRec and 321 with no recurrence (NoRec)) were analyzed. The rates of positive ALDH1 in ERec, LRec and NoRec groups were 18%, 13% and 8%, respectively. ALDH1 positivity was significantly higher in ERec compared with NoRec group (p<0.01). There was no significant difference between LRec and NoRec group (p=0.12). Positive ALDH1 showed significantly shorter DFS and OS in multivariate analyses (DFS: p=0.03, OS: p<0.01). Especially, that was the significantly prognostic factor in the Luminal B like tumor with adjuvant or neoadjuvant chemotherapy (p=0.01), but not in those without any chemotherapy (p=0.53). High TILs in ERec, LRec and NoRec was 1.1%, 1.5% and 3.7%, respectively. There was no significant difference among three recurrent groups (p=0.13). High TILs was not significantly associated with DFS (p=0.09) and OS (p=0.72). However, there was significant correlation between High TILs and DFS in Luminal B like group (p=0.04) and ALDH1-negative group (p=0.02).

Conclusion: In ER-positive, and HER2-negative breast cancer, ALDH1 was an independent prognostic factor (a predictor of ERec, but not LRec). ALDH1 might be a predictor of benefit from chemotherapy in Luminal B like subtype. TILs was neither a predictor of ERec nor LRec. However, significance of TILs as prognostic factor might differ depending on subtypes and cancer stemness.

Citation Format: Miyoshi Y, Shien T, Ogiya A, Ishida N, Yamazaki K, Horii R, Horimoto Y, Masuda N, Yasojima H, Inao T, Osako T, Takahashi M, Tomioka N, Hagio K, Endo Y, Hosoda M, Yamashita H. Prognostic value of aldehyde dehydrogenase 1 (ALDH1) and tumor infiltrating lymphocytes (TIL) to predict the late recurrence in ER positive, HER2 negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-15.

[Evaluation of superior transseptal approach for the removal of left atrial myxoma]

We compared the operative outcomes among 14 patients who underwent the removal of left atrial myxoma with four different approaches; right lateral (n = 2), transseptal bi-atrial (Dubost, n = 4), conventional transseptal (n = 4) and superior transseptal approach (STA, n = 4). Concomitant operations were performed in 4 cases (CABG, two; aortic valvuloplasty, one; mitral valve replacement, one), and two out of 4 cases were in the STA group. The mean operation, cardiopulmonary bypass and aortic cross-clamp times were shorter in the STA group compared to the other three group. The total amount of postoperative drain discharge and the peak value of creatine kinase were also lower in the STA group compared to the other three groups. Among the patients in sinus rhythm before operation, the use of STA was associated with a greater incidence (100%) of postoperative atrial fibrillation or junctional rhythm. These rhythm disturbances were temporary, and all returned to sinus rhythms during hospital stay. We conclude that STA is an excellent approach with a nice surgical view to expose and remove the left atrial myxoma.