Human Pathology (2013) 44, 2338–2345
www.elsevier.com/locate/humpath
Original contribution
Androgen and androgen-metabolizing enzymes in metastasized lymph nodes of breast cancer☆ Yukiko Shibahara MD, PhD a,⁎, Yasuhiro Miki DVM, PhD a , Chikako Sakurada BA a , Keiko Uchida a , Shuko Hata PhD a , Keely McNamara PhD a , Tomomi Yoda BA a , Kiyoshi Takagi PhD b , Yasuhiro Nakamura MD, PhD a , Takashi Suzuki MD, PhD b , Takanori Ishida MD, PhD c , Noriaki Ohuchi MD, PhD c , Hironobu Sasano MD, PhD a a
Department of Pathology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-Machi, Aobaku, Sendai, Miyagi, Japan, 980-8575 b Department of Pathology and Histotechnology, Tohoku University School of Graduate Medicine, 2-1 Seiryo-Machi, Aobaku, Sendai, Miyagi, Japan, 980-8575 c Department of Surgical Oncology, Tohoku University School of Graduate Medicine, 2-1 Seiryo-Machi, Aobaku Sendai, Miyagi, Japan, 980-8575 Received 17 January 2013; revised 12 April 2013; accepted 17 April 2013
Keywords: Breast cancer; Immunohistochemistry; Androgen; Lymph node; Metastasis; Steroid metabolism
Summary Androgen receptor and androgen metabolizing enzymes, 17β-hydroxysteroid dehydrogenase type 5 (17βHSD5) and 5α-reductase1 (5α1), are frequently detected in primary tumor of breast cancer, but their status in metastatic lymph nodes has not been examined. The biological role of androgen in breast cancer and its metastatic process also remain unknown. In this study, we used immunohistochemistry to localize the expression of androgen receptor, 17βHSD5, and 5α1 in primary tumors and paired metastatic lymph nodes and correlated the findings with clinicopathologic factors of individual patients. Approximately 70% of primary tumors and paired metastatic lymph nodes expressed androgen receptor, with significant correlation between both lesions. However, 17βHSD5 and 5α1 immunoreactivity was decreased in metastatic lymph nodes. Alone or in tandem with androgen receptor, 5α1 was associated with significantly lower Ki-67 index, lower pathologic grade, and higher estrogen receptor positivity, but androgen receptor/5α1 double positivity in lymph nodes was associated with larger lymph node metastasis and higher TNM stage. In conclusion, androgen receptor immunoreactivity remained stable during the process of metastasis, whereas androgen-metabolizing enzymes decreased. Although results of our study and previous reports imply additional roles of androgen metabolism in the metastasis process, especially conversion by 5α1, there may be divergence between its effects on primary tumor and those in metastatic lymph nodes. © 2013 Elsevier Inc. All rights reserved.
1. Introduction ☆ Conflict of interest: The authors declare that they have no conflict of interest. ⁎ Corresponding author. E-mail address:
[email protected] (Y. Shibahara).
0046-8177/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.humpath.2013.04.021
The androgen receptor (AR) is positive in 80% of breast cancer patients [1]. Androgen is generally recognized as a tumor suppressor, but its role has remained controversial [2]. This controversy is especially centered around estrogen
Androgen in metastatic lymph nodes of breast cancer receptor (ER)–negative cancers, including the triple-negative breast cancer subtype (ER−/progesterone receptor [PR]−/ human epidermal growth factor receptor type2 [HER2]−) that is difficult to treat. Although the results of in vitro experiments have suggested androgens as a growth-promoting factor, studies of histologic samples indicate that the presence of AR is associated with better prognosis [3,4]. Resolving this issue is important as triple-negative breast cancer subtype represents approximately 25% of all breast cancers, and androgens are a potentially promising therapeutic target. Although much of the current research has focused on the role of androgens in the primary tumor (PT), research into any potential role of androgens in metastasis has been unexplored. It is becoming apparent that steroid metabolism plays an important role in metastatic cancer as various reports have suggested biological roles for estrogenic pathways. Studies examining ER expression have reported decreased immunoreactivity in the metastatic lymph nodes, which may explain the development of resistance to endocrine therapy during tumor progression [5]. In contrast to this, we recently reported that aromatase expression in metastatic lymph nodes of ERpositive breast cancer is maintained [6], suggesting that cells retain their ability to synthesize estrogens following metastasis. In contrast, although the expression of AR in distant metastasis has been examined recently [7], the role of androgens in metastatic lymph nodes is unexplored. The intracrine mechanisms of androgens in human breast cancer tissues can be summarized as follows: androstenedione is converted into testosterone by 17β-hydroxysteroid dehydrogenase type 5 (17βHSD5); subsequently, testosterone is metabolized into dihydrotestosterone (DHT) by the actions of 5α-reductase, type1 and type 2 (5α1 and 5α2). We have previously shown that 5α1 is the dominant isoform in breast cancer tissues between these 2 isoforms, 5α1 and 5α2 [8]. In an alternate pathway, testosterone is metabolized into estradiol by the aromatase enzyme. As estradiol promotes tumor growth, the role of androgen depends on the relative expression levels of these enzymes. Therefore, it is essential to examine the combined expression of 17βHSD5 and 5α1 in addition to AR, and to the best of our knowledge, this is the first study to do so in metastatic lymph nodes using immunohistochemistry.
2. Materials and methods 2.1. Patients Surgical pathology specimens of breast cancer were obtained from 57 patients who underwent breast and lymph node excision between 2003 and 2011 at the Department of Surgery, Tohoku University Hospital (Sendai, Japan). The Ethics Committee at Tohoku University School of Medicine approved the research protocol for this study. Only the cases positive for lymph node metastasis but negative for clinical distant metastasis were included. Exclusion criteria based on study design were cases treated with neoadjuvant therapy
2339 and cases with small lymph node metastasis, in which multiple tissue sectioning was not possible technically. The mean age of the patients was 57.5 years (range, 2882). Clinical data were retrieved from the patients' charts, and the pathologic types and histologic grades of individual tumors (Table 1) were evaluated by 3 of the authors (Y. S., C. S., and Y. M.). All specimens were fixed with 10% formalin and embedded in paraffin. Of the 57 cases, 44 ER-positive cases were used in our previous article for immunohistochemistry [6], and clinicopathologic data of those cases were used in this study.
2.2. Antibodies Methodologies for AR (AR441; DakoCytomation, Kyoto, Japan), 17βHSD5 (Sigma-Aldrich, St Louis, MO), and 5α1 Table 1
Patient characteristics
Patient characteristics Age (y) Median Mean (range) Age class ≤40 41-50 51-60 61-70 ≥71 pTNM stage a I II III Primary tumor size (cm) ≤2 2-5 N5 Tumor grade b 1 2 3 Pathologic type Scirrhous Papillotubular Solid-tubular Mucinous Metaplastic IMPCa No. of metaLN 1-3 (pN1) 4-9 (pN2) ≥10 (pN3)
n
%
56 58
(28-82)
5 11 21 8 12
8.8 19.3 36.8 14.0 21.1
37 20 0
64.9 35.1 0.0
21 33 3
36.8 57.9 5.3
12 22 23
21.1 38.6 40.4
36 7 12 1 1 3
63.2 12.3 21.1 1.8 1.8 5.3
38 15 4
66.7 26.3 7.0
Abbreviations: IMPCa, invasive micropapillary carcinoma; metaLN, metastatic lymph nodes. a pTNM (pathological TNM) stage was determined according to UICC, Seventh Edition, 2009 [21]. b Tumor grade was evaluated according to the Nottingham Histological Grading Method [22].
2340
Y. Shibahara et al.
(Abcam, Cambridge UK) were previously described [7]. The dilutions of antibodies used were as follows: AR, 1:50; 17βHSD5, 1:200; 5α1, 1:1000. A Histofine Kit (Nichirei, Tokyo, Japan) was used. Other antibodies used were as follows: ERα (ER1D5; Immunotech, Marseilles, France), PR (MAB429; Chemicon International, Temecula, CA), HER2, and Ki-67 (MIB1; DakoCytomation).
2.3. Evaluation of immunohistochemistry Immunoreactivity of AR, ER, PR, and Ki-67 was detected in the nuclei of cancer cells. To quantitatively assess immunoreactivity, positive cells were counted in 10 random optic fields, using a light microscope equipped with 50× objectives. When 10 optic fields were unavailable, all cancer cells were evaluated. Subsequently, the percentage of immunoreactivity, that is, labeling index (LI), was determined. AR, ER, and PR LI greater than 10% was considered positive [9,10]. Immunoreactivity of 17βHSD5 and 5α1 was detected in the cytoplasm of cancer cells and assessed in a semiquantitative manner with greater than 10% considered positive [8]. HER2 immunoreactivity was detected at the membrane of cancer cells and was evaluated according to the manufacturer's grading system (HercepTest 0, 1+, 2+, 3+; DakoCytomation).
2.4. Statistical analysis Correlations between ER, AR, and Ki-67 LIs in PTs and metastatic lymph nodes were evaluated using regression analysis. Correlations between 17βHSD5 and 5α1 in PT and metastatic lymph nodes were evaluated using the χ2 test. Associations among ER, PR, AR, 17βHSD5, 5α1, and Ki-67 as well as 17βHSD5/5α1, AR/5α1 status, and clinicopathologic factors were evaluated using the Mann-Whitney U test and the χ2 test or Fisher exact t test. P b .05 was regarded as statistically significant.
3. Results
Fig. 1 Regression analysis of AR (A), estrogen receptor (B), and Ki-67 (C) LI between PT and metastatic lymph nodes.
3.1. Androgen receptor In the complete cohort, 40 (70.2%) of 57 PTs and 40 (70.2%) of 57 metastatic lymph nodes were AR positive. When subdivided by ER status, 31 (70.5%) of 44 cases of PT and 30 (68.2%) of 44 metastatic lymph nodes of ER-positive tumors and 9 (69.2%) of 13 PTs and 10 (76.9%) of 13 metastatic lymph nodes of ER-negative tumors were AR positive. The average AR LI was 45.2% in PT and 42.1% in metastatic lymph nodes. A significant correlation between AR expression in PT and metastatic lymph nodes was detected (y = 0.4609x + 21.75, P = .0005, R2 = 0.1983) (Fig. 1A). We also found a significant correlation between AR expression in PT and
metastatic lymph nodes in ER-negative tumors (y = 0.7764x + 11.37, P = .0019, R2 = 0.5992), but not in ER-positive tumors (y = 0.3063x + 26.27, P= .0536, R2 = 0.08586). ER expression in PTs and metastatic lymph nodes was also correlated (ER: y = 0.8506x + 17.96, P b .0001, R2 = 0.6832; Ki-67: y = 1.043x + 5.707, P b .0001, R2 = 0.7684) (Fig. 1B and C).
3.2. Androgen-metabolizing enzymes In both PTs and metastatic lymph nodes, 5α1 and 17βHSD5 were located in the cytoplasm of breast cancer cells (Fig. 2). Positive 17βHSD5 staining was found in 43 (75.4%) of 57 PTs and 30 (52.6%) of 57 metastatic lymph
Androgen in metastatic lymph nodes of breast cancer
2341
Fig. 2 Hematoxylin-eosin staining (left column) and immunohistochemistry (right column) for 17βHSD5 (A) and 5α1 (B) of PT (upper row) and metastatic lymph nodes (lower). Immunoreactivity for 17βHSD5 and 5α1 was detected in cytoplasm of cancer cells.
2342
Y. Shibahara et al. either PT or metastatic lymph nodes was correlated with any of the clinicopathologic factors. 17βHSD5/5α1 status as well as AR/5α1 status and their correlation with clinicopathologic factors were analyzed. We subsequently divided the cases into the following 2 groups: 17βHSD5/5α1 double positive (+/+) versus others and AR/ 5α1 double positive (+/+) versus others. The 17βHSD5/5α1 (+/+) group in PT was correlated with significantly lower pathologic grade (P = .0004) and tended to be correlated with higher AR LI (P = .0523). No significant association was detected between other clinicopathologic factors in PT, and metastatic lymph nodes were not correlated in any way (Table 4). The AR/5α1 (+/+) group in PT was correlated with significantly lower pathologic grade (P = .0029), lower Ki67 LI (P = .0129), and significantly higher ER LI (P = .0091). The AR/5α1 (+/+) group in metastatic lymph nodes was significantly associated with larger metastatic lymph node size (P = .0246) and higher TNM stage (P = .0465) and tended to present with a larger number of metastatic lymph nodes (P = .0549) (Table 5).
Table 2 Difference in 17βHSD5 and 5α1 expression between PT and metastatic lymph nodes 17βHSD, n (%) + PT
43 (75.4%) metaLN 30 (52.6%)
P
−
5α1, n (%) +
P
−
14 .0012 33 24 b.0001 (24.6%) (57.9%) (42.1%) 27 9 48 (47.4%) (15.8%) (84.2%)
NOTE. Data were statistically analyzed using the χ2 test. P b .05 was considered significant.
nodes, and 33 (57.9%) of 57 PTs and 9 (15.8%) of 57 metastatic lymph nodes were 5α1 positive. Both 17βHSD5 and 5α1 were more frequently detected in PT compared with metastatic lymph nodes (17βHSD5, P = .012; 5α1, P b .0001; Table 2). AR was not mutually correlated with 17βHSD5 and 5α1. In PT, 5α1-positive cases were significantly correlated with lower pathologic grade (P b .0001) and higher ER LI (P = .0091) (Table 3). In PT, 5α1 positivity was significantly associated with low Ki-67 LI (%) (P = .0072), as was the case with ER in PT (ER+, 13.20 ± 1.684, n = 44; ER−, 50.25 ± 4.906, n = 13; P b .0001) and metastatic lymph nodes (ER+, 18.85 ± 2.451; ER−, 60.38 ± 5.035; P b .0001). In metastatic lymph nodes, 5α1 positivity tended to be correlated with low pathologic grade (P = .0514). We did not find any correlation between other clinicopathologic factors and 5α1 positivity. Neither AR nor 17βHSD5 in
Table 3
4. Discussion In this study, AR immunoreactivity was concordant between PT and metastatic lymph nodes. This indicates that AR expression is maintained in the breast cancer metastasis process, which is similar to a previous report [7]. As DHT is synthesized from androstenedione to testosterone by
Association between 5α1 status and clinicopathologic factors in 57 paired PT and metastatic lymph nodes of breast cancer PT, n (%)
Age (y) Pathologic grade 1+2 3 No. of metaLNs Size (cm) metaLN Tumor Stage II III ER LI (%) PR LI (%) Ki-67 LI (%) AR LI (%) HER2 Positive Negative
P
+ (n = 33)
− (n = 24)
59.27 ± 1.856
55.00 ± 3.320
27 (47.4%) 6 (10.5%) 3.697 ± 0.7157
Lymph nodes, n (%)
P
+ (n = 9)
− (n = 48)
.2415
56.56 ± 4.874
57.65 ± 1.913
.893
7 (12.3%) 17 (29.8%) 4.333 ± .9357
b.0001 a
26 (45.6%) 22 (38.6%) 3.833 ± 0.6464
.0514
.9705
8 (14.0%) 1 (1.8%) 4.667 ± 1.067
.1295
1.067 ± 0.1196 2.767 ± 0.2669
1.129 ± .1433 2.239 ± .2548
.7027 .0704
1.344 ± .2652 2.444 ± .3346
1.046 ± 0.09593 2.465 ± 0.2144
.2708 .7263
22 (38.6%) 11 (19.3%) 75.49 ± 4.938 41.34 ± 6.783 14.56 ± 2.121 50.91 ± 6.287
15 (26.3%) 9 (15.8%) 38.31 ± 8.417 25.66 ± 7.351 31.39 ± 5.075 34.88 ± 7.809
.7448
4 (7.0%) 5 (8.8%) 81.80 ± 1.35 37.40 ± 13.50 16.26 ± 2.877 36.11 ± 12.62
33 (57.9%) 15 (26.3%) 66.42 ± 5.937 44.02 ± 5.681 30.59 ± 3.675 43.23 ± 5.680
.2532
6 (10.5%) 27 (47.4%)
8 (14.0%) 16 (28.1%)
3 (5.3%) 6 (1.5%)
9 (15.8%) 39 (68.4%)
.0091 a .0854 .0072 a .1165 .2241
.2905 .7456 .3061 .4377 .9668
NOTE. 5α1 status was evaluated by immunohistochemistry, and immunoreactivity greater than 10% was considered positive. Association with pathologic grade, stage, and HER2 status was evaluated using a cross-table using the χ2 test or Fisher exact t test. Other data are presented as mean ± 95% confidence interval and were evaluated using the Mann-Whitney U test. a P b .05 was considered significant.
Androgen in metastatic lymph nodes of breast cancer Table 4 cancer
2343
Association between 17βHSD5/5α1 status and clinicopathologic factors in 57 paired PT and metastatic lymph nodes of breast PT, n (%)
Age (y) Pathologic grade 1+2 3 No. of metaLN Size (cm) metaLN Tumor Stage II III ER LI (%) PR LI (%) AR LI (%) Ki-67 LI (%) HER2 Positive Negative
P
+/+ (n = 26)
Others (n = 31)
59.12 ± 2.208
56.10 ± 2.680
22 (38.6%) 4 (7.0%) 3.154 ± 0.3871
12 (21.1%) 19 (33.3%) 4.645 ± 0.9843
1.092 ± 0.1339 2.092 ± 0.2229
Lymph nodes, n (%)
P
+/+ (n = 5)
Others (n = 52)
.5165
55.20 ± 8.969
57.69 ± 1.773
.7168
.0005 a
30 (52.6%) 22 (38.6%) 3.846 ± 0.5994
.6384
.9325
4 (7.0%) 1 (1.8%) 5.200 ± 1.855
.2958
1.094 ± 0.1263 2.771 ± 0.2800
.9651 .087
1.260 ± 0.3982 2.280 ± 0.4375
1.077 ± 0.09348 2.479 ± 0.2015
.6952 .9727
17 (29.8%) 9 (15.8%) 73.23 ± 6.068 40.72 ± 7.846 54.50 ± 6.988 15.48 ± 2.598
20 (35.1%) 11 (19.3%) 48.60 ± 7.446 29.72 ± 6.567 35.48 ± 6.729 26.82 ± 4.237
.9454
2 (3.5%) 3 (5.3%) 91.24 ± 1.096 25.24 ± 12.76 31.60 ± 14.58 13.32 ± 3.419
35 (61.4%) 17 (29.8%) 66.70 ± 5.703 44.68 ± 5.536 43.12 ± 5.484 29.77 ± 3.428
.3319
5 (8.8%) 21 (36.8%)
9 (15.8%) 22 (38.6%)
2 (3.5%) 3 (5.3%)
10 (17.5%) 42 (73.7%)
.0457 a .2674 .0523 .0758 .5392
.3051 .2732 .5386 .2151 .2812
NOTE. 17βHSD5/5α1 status was evaluated by immunohistochemistry, and “+/+” represents cases positive for both 17βHSD5 and 5α1. Association with pathologic grade, stage, and HER2 status was evaluated using a cross-table using the χ2 test or Fisher exact t test. Other data are presented as mean ± 95% confidence interval and were evaluated using the Mann-Whitney U test. a P b .05 was considered significant.
17βHSD5 and testosterone to DHT by 5α-reductase, we determined the expressions of these androgen-metabolizing enzymes in metastatic lymph nodes for the first time. Although 2 isoforms of 5α-reductase, 5α1 and 5α2, exist, we Table 5
have previously reported immunoreactivity of 5α1 in PTs to be 58%, whereas that of 5α2 is only 15% [9], suggesting intratumoral DHT concentration to be mainly determined by 5α1. Considering the limited nature of the cases used in this
Association between AR/5α1 status and clinicopathologic factors in 57 paired PT and metastatic lymph nodes of breast cancer PT, n (%)
Age (y) Pathologic grade 1+2 3 No. of metaLN Size (cm) metaLN Tumor Stage II III ER LI (%) PR LI (%) Ki-67 LI (%) HER2 Positive Negative
P
Lymph nodes, n (%)
P
+/+ (n = 26)
Others (n = 31)
+/+ (n = 5)
Others (n = 52)
59.35 ± 2.214
55.90 ± 2.669
.3830
64.00 ± 5.128
56.85 ± 1.864
.2772
21 (36.8%) 5 (8.8%) 3.808 ± 0.8876
13 (22.8%) 18 (31.6%) 4.097 ± 0.7454
.0029 a
30 (52.6%) 22 (38.6%) 3.885 ± 0.6206
.6384
.9453
4 (7.0%) 1 (1.8%) 4.800 ± 0.4899
.0549
1.058 ± 0.1396 2.254 ± 0.3096
1.123 ± 0.1217 2.635 ± 0.2257
.5961 .0948
1.800 ± 0.3271 2.860 ± 0.4377
1.025 ± 0.09029 2.423 ± 0.2009
.0465 .3515
17 (29.8%) 9 (15.8%) 75.80 ± 5.947 39.23 ± 7.724 14.05 ± 2.291
20 (35.1%) 11 (19.3%) 46.45 ± 7.250 30.96 ± 6.726 28.02 ± 4.241
.9454
1 (1.8%) 4 (7.0%) 90.62 ± 2.530 29.66 ± 18.41 17.20 ± 2.237
36 (63.2%) 16 (28.1%) 66.76 ± 5.705 44.26 ± 5.441 29.39 ± 3.465
.0276 a
6 (10.5%) 20 (35.1%)
8 (14.0%) 23 (40.4%)
1 (1.8%) 4 (7.0%)
11 (19.3%) 41 (71.9%)
.0091 a .2303 .0129 a .8115
a
.3179 .5109 .7352 1.0000
NOTE. AR/5α1 status was evaluated by immunohistochemistry, and “+/+” represents cases positive for both AR and 5α1. Association with pathologic grade, stage, and HER2 status was evaluated using a cross-table using the χ2 test or Fisher exact t test. Other data are presented as mean ± 95% confidence interval and were evaluated using the Mann-Whitney U test. a P b .05 was considered significant.
2344 study, we decided to limit the examination to the more prevalent of the 2 isoforms. In contrast to AR, immunohistochemical evaluation of 17βHSD5 and 5α1 in PT and metastatic lymph nodes indicated a significant decrease in the expression of these enzymes in metastatic lymph nodes: 75% to 53% and 58% to 16%, respectively. The disparity between the conservation of AR but loss of enzyme expression between PT and metastatic lymph nodes suggests that intratumoral metabolism rather than receptor expression may be a key component in predicting breast cancer behavior. Although many studies have focused on diverse roles for AR in tumor biology [11-15], the results of our present study suggest that AR is not a lone entity when assessing the effect of androgens in breast cancer prognosis. These data underline the importance of assessing in tandem steroid-metabolizing enzymes and their receptors, as our data suggest that loss of enzymatic machinery rather than receptor expression may be the most important change between PT and metastatic lymph nodes. Previous studies have suggested that tumors expressing high levels of 17βHSD5 were associated with poor prognosis [16], whereas tumors positive for 5α1 were associated with better prognosis [17]. The latter finding in PT is supported by our own results, as we observed correlation of 5α1 positivity as well as AR/5α1 double positivity with lower Ki-67 LI and lower pathologic grade, factors that predict a better outcome [18,19]. In addition, 5α1-positive tumors and AR/5α1 double-positive tumors were more likely to be ER positive —a tumor type known to have better prognosis than its ERnegative counterpart [20]. Therefore, in PTs, it is suggested that high 5α1 expression leads to high intratumoral DHT concentration. In combination with AR expression, this increased androgenic state is predictive of a less aggressive tumor phenotype [17]. A different pattern was observed in metastatic lymph nodes where AR/5α1 double positivity but not 5α1 alone was associated with larger metastatic lymph node size and higher TNM stage. Results of this study suggest that androgen metabolism in lymph nodes may have an adverse effect on prognosis; however, further studies are required to confirm this novel finding. In contrast to 5α1, 17βHSD5 was not correlated with any of the factors examined in this study in either PT or metastatic lymph nodes. As 17βHSD5 is upstream of 5α1 in steroid synthetic pathways, we suggest that this result indicates that the production of the highly potent, nonaromatizable androgen DHT is the most important element in androgen actions in breast cancer. On this basis, it would be reasonable for 5α1 but not 17βHSD5 to be closely correlated with clinical characteristics. Our hypothesis regarding the underlying mechanism of how 5α1 may be protective in breast cancer is 2-fold. First, the increased intratumoral DHT binds to AR to promote an antiproliferative program [2]. Second, increased 5α1 expression depletes the amount of testosterone available to be aromatized to estrogens, hence reducing the level of proproliferative estrogenic signal. To verify this, we attempted
Y. Shibahara et al. to factor aromatase into our present analysis using aromatase expression LI data from our previous study [6] and evaluated the aromatase/5α1 ratio with clinicopathologic factors (data not shown). However, as aromatase prevalence and intensity greatly exceeded that of 5α1, the aromatase/5α1 ratio was always weighted toward aromatase. Therefore, the ratio of the 2 and its correlation with clinicopathologic factors were insignificant and unclear. In conclusion, we demonstrated for the first time high rates of concordance in AR expression and discordance in enzyme expression between PTs and paired lymph node metastases. These data suggest an adverse role of androgens in the metastatic process, especially the conversion of testosterone to DHT via the 5α1 enzyme.
Acknowledgments We thank Ono K, Ise K, and Kumasaka H for technical assistance.
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