Mol Cell Biochem DOI 10.1007/s11010-015-2384-4

Overexpression of HMGA1 correlates with the malignant status and prognosis of breast cancer Ruixue Huang1 • Dequn Huang2 • Weirong Dai3 • Fei Yang1

Received: 10 January 2015 / Accepted: 5 March 2015 Ó Springer Science+Business Media New York 2015

Abstract High mobility group A1 (HMGA1), as a major member of HMGA family, plays an important part in promotion of cell proliferation and motility, induction of epithelial-mesenchymal transition, and maintenance of stemness, but little is known about the pathological role of HMGA1 in breast cancer patients. The aim of this study was to identify the pathological roles of HMGA1 in breast cancer. In our results, we found that mRNA and protein expression levels of HMGA1 were markedly higher in breast cancer tissues than in normal breast tissues. Using immunohistochemistry, high levels of HMGA1 protein were positively correlated with the status of histological grade (I–II vs. III–IV; P = 0.023), clinical stage (I–II vs. III–IV; P = 0.008), tumor size (T1–T2 vs. T3–T4; P = 0.015), lymph node metastasis (N0–N1 vs. N2–N3; P = 0.002), distant metastasis (M0 vs. M1; P \ 0.001), and triple-negative breast cancer (No vs. Yes; P = 0.014) of breast cancer patients. Patients with higher HMGA1 expression had a significantly shorter overall survival time than did patients with low HMGA1 expression. Multivariate analysis indicated that the level of HMGA1 expression was an independent prognostic indicator Ruixue Huang, Dequn Huang, Weirong Dai have contributed equally to this study. & Fei Yang [email protected] 1

Department of Occupational and Environmental Health, School of Public Health, Central South University, 110 Xiangya Road, Changsha 410078, Hunan, China

2

Medical Examination Center, No. 1 Hospital of Zhuzhou City, Zhuzhou 421000, Hunan, China

3

Hunan Prevention and Treatment Institute of Occupational Diseases, Changsha 410078, Hunan, China

(P \ 0.001) for the survival of patients with breast cancer. In conclusion, HMGA1 plays an important role on breast cancer aggressiveness and prognosis and may act as a promising target for prognostic prediction. Keywords Biomarker

HMGA1  Breast cancer  Prognosis 

Introduction Breast cancer is the most common type of malignancy among women and is one of the leading causes of cancerrelated deaths in the world [1, 2]. Although advancements of diagnosis and treatment have improved the survival of breast cancer patients, the clinical outcome of breast cancer patients remains unsatisfactory [3]. Poor prognosis has been attributed to tumor invasion, metastasis, and recurrence. Therefore, it is very important to identify biomarkers which provide early diagnosis, accurate prognosis prediction, and novel therapeutic target. High mobility group A1 (HMGA1), as a major member of HMGA family, plays an important part in promotion of cell proliferation and motility, induction of epithelialmesenchymal transition, and maintenance of stemness [4, 5]. HMGA1 proteins modulate gene expression by altering chromatin structure and orchestrating the assembly of transcription factor complexes to enhanceosomes within enhancer or promoter regions throughout the genome [6]. Recent studies identified HMGA1 oncogene as a key factor overexpressed in several types of human cancer, such as prostate cancer [7, 8], colorectal cancer [9], breast cancer [10], pancreatic cancer [11], and ovarian cancer [12]. Overexpression of the HMGA1 gene in human breast cancer has been demonstrated, with a positive correlation

123

Mol Cell Biochem

between HMGA1 protein levels and the metastatic phenotype of human breast cancer cell lines [13]. Moreover, HMGA1 is fundamental in sustaining stem cell and metastatic properties through cooperating with the Wnt/beta-catenin and Pin1/mutant p53 signaling pathways in basal-like breast cancer subtype [14]. In triple-negative breast cancer cells, HMGA1 is a master regulator of tumor progression in breast cancer by reprogramming cancer cells through stem cell transcriptional networks [15]. Although associations between HMGA1 expression and clinicopathological features including prognosis have been investigated in various human cancer such as lung cancer [16], colorectal cancer [17], liver cancer [18], pancreatic adenocarcinoma [19–21], and uveal melanomas [22], little is known about HMGA1 in breast cancer patients. In order to identify the role of HMGA1 in the pathogenesis of breast cancer, we investigated the relationship of HMGA1 expression with clinicopathological features, including the survival of patients. We found that mRNA and protein expression levels of HMGA1 were higher in breast cancer tissues than those in adjacent normal tissues. Moreover, the relatively higher protein expression of HMGA1 was significantly associated with breast cancer progression and poor prognosis.

PrimeScript RT Master Mix (Perfect Real Time) (Takara, Japan) according to manufacturer instructions. The sequence-specific forward and reverse primers sequences for HMGA1 were 50 -AGGAAAAGGACGGCACTGAGAA-30 and 50 -CCCCGAGGTCTCTTAGGTGTTGG-30 , respectively. Forward and reverse primers sequences for GAPDH were 50 -ATGGGGAAGGTGAAGGTCG-30 and 50 -GGGG TCATTGATGGCAACAATA-30 , respectively. qPCR was performed using SYBR Premix Ex TaqTM II (Takara, Japan) on a LightCycler (Roche Diagnostics, USA). Relative quantification of mRNA expression was calculated using the 2-DDCt method. The raw data were presented as the relative quantity of target mRNA, normalized with GAPDH, and relative to a calibrator sample. All qRTPCR reactions were performed in triplicate. Western blot Western blot was carried out according as previously described with anti-HMGA1 (1:1000; Abcam, clone EPR7839). HRP-conjugated anti-rabbit IgG antibody was used as the secondary antibody (1:2000; Cell signaling technology). Signals were detected using enhanced chemiluminescence reagents (Pierce). Immunohistochemistry

Materials and methods Sample collection A total of 20 freshly frozen breast cancer samples and paired adjacent normal samples were collected from No. 1 hospital of Zhuzhou city. All fresh samples were immediately preserved in liquid nitrogen. One hundred and fiftytwo paraffin-embedded breast cancer specimens were retrieved from No. 1 hospital of Zhuzhou city. No patients had received any form of tumor-specific therapy before diagnosis. Before the use of these clinical samples, prior consents from the patients and approval from the Institutional Ethics Committee of No. 1 hospital of Zhuzhou city were obtained. The histopathological diagnosis of all samples was, respectively, diagnosed by two pathologists. The clinical staging was based on the 7th edition of the AJCC Cancer Staging Manual. The clinical follow-up time of patients ranged from 6 to 91 months. Overall survival (OS) was defined as the interval from the date of diagnosis to breast cancer-related death. RT-qPCR To quantitate mRNA expression, total RNA was extracted from clinical samples with RNAiso Plus (Takara, Japan). The isolated total RNA was reverse transcribed using the

123

Paraffin sections from breast cancer specimens were deparaffinized in xylene and rehydrated in a descending ethanol series (100, 95, 90, 80, 70 % ethanol) and doubledistilled water according to standard protocols [23]. Heatinduced antigen retrieval was performed in citrate buffer and boiled for 10 min. After antigen retrieval, sections were treated with 3 % hydrogen peroxide and 1 % bovine serum albumin to block the endogenous peroxidase activity and non-specific binding. The sections were incubated with HMGA1 antibody (Abcam, clone EPR7839, dilution 1:100) overnight at 4 °C. After phosphate-buffered saline washing, the tissue sections were incubated with the biotinylated secondary antibody and streptavidin–horseradish peroxidase complex, each for 20 min at room temperature. Diaminobenzidine was used as the chromogen, and tissue sections were counterstained with haematoxylin and then viewed under a bright-field microscope. Evaluation of staining The tissue sections stained immunohistochemically for HMGA1 were reviewed, and scored separately by two pathologists blinded to the clinical parameters. Any disagreements were arbitrated by the third pathologists. For HMGA1 assessment, staining intensity was scored as 0 (negative), 1 (weak), 2 (medium), and 3 (strong). Extent of

Mol Cell Biochem

staining was scored as 0 (0 %), 1 (1–25 %), 2 (26–50 %), 3 (51–75 %), and 4 (76–100 %) according to the percentages of the positive staining areas in relation to the whole carcinoma area [23, 24]. The sum of the staining intensity and staining extent scores was used as the final staining score (0–7) for HMGA1. For statistical analysis, the final staining scores of 0–4 and 5–7 were, respectively, considered to be low and high expression. Statistical analysis All statistical analyses were performed using SPSS version 17.0 and GraphPad 5.0 software. Data were presented as mean ± SD. The Wilcoxon Signed Rank test was applied to test the differential mRNA expression of HMGA1 in cancer tissues compared to paired normal tissues. The Chi-square test was applied to the examination of relationship between HMGA1 expression levels and clinicopathologic characteristics. Survival curves were plotted using the Kaplan– Meier method and compared using the log-rank test. The significance of survival variables was analyzed using the Cox multivariate proportional hazards model. A P value of less than 0.05 was considered statistically significant.

Fig. 1 Overexpression of HMGA1 in breast tissues. a The mRNA expression of HMGA1 was increased in breast cancer tissues compared with adjacent normal tissues by RT-qPCR. b The protein expression of HMGA1 was increased in breast cancer tissues than those in adjacent normal tissues by Western blot

Results

(M0 vs. M1; P \ 0.001), and triple-negative breast cancer (No vs. Yes; P = 0.014). However, there was no significant correlation between HMGA1 expression and age (P = 0.137).

HMGA1 mRNA and protein were overexpressed in breast cancer tissue

HMGA1 overexpression was an independent poor prognostic factor in breast cancer patients

In order to assess the role of HMGA1 in breast cancer, we performed real-time PCR to measure the expression of HMGA1 mRNA transcripts in twenty paired breast cancer tissues and adjacent normal tissues. Compared with adjacent normal tissues, breast cancer tissues showed higher expression levels of HMGA1 mRNA (P \ 0.001, Fig. 1a). We measured the expression levels of HMGA1 protein in paired breast cancer tissues and adjacent normal tissues using Western blot. HMGA1 protein was overexpressed in breast cancer tissues compared with adjacent normal tissues (Fig. 1b).

To explore the prognostic value of HMGA1 expression in breast cancer, we measured the association between the levels of HMGA1 expression and patients’ survival using Kaplan–Meier analysis with the log-rank test. In 152 breast cancer patients with prognosis information, we found that the level of HMGA1 protein expression was significantly associated with the OS of breast cancer patients, as patients with lower levels of HMGA1 expression had better survival than those with higher levels of HMGA1 expression (P \ 0.001, Fig. 3). Furthermore, we also found that increased expression of HMGA1 showed poor prognosis in breast cancer patients, regardless of clinical stage, T classification, N classification, distant metastasis, and triplenegative breast cancer. Multivariate analysis showed that increased HMGA1 expression was an independent poor prognostic factor for patients with breast cancer (Table 2).

Correlation between HMGA1 and clinicopathological features in breast cancer patients We next analyzed the correlation between the expression of HMGA1 protein and clinicopathological characteristics of breast cancer (Fig. 2). As summarized in Table 1, HMGA1 was associated significantly with histological grade (I–II vs. III–IV; P = 0.023), clinical stage (I–II vs. III–IV; P = 0.008), tumor size (T1–T2 vs. T3–T4; P = 0.015), lymph node metastasis (N0–N1 vs. N2–N3; P = 0.002), distant metastasis

Discussion HMGA1, as a major member of HMGA family, has been implicated to play a role in promotion of cell proliferation and motility, induction of epithelial-mesenchymal

123

Mol Cell Biochem

Fig. 2 Immunohistochemical staining of HMGA1 in breast cancer tissues (original magnification 9400). a Negative expression of HMGA1 in normal breast tissues (Intensity score = 0). b Weak

Table 1 Correlations between HMGA1 protein expression and clinicopathological characteristics in breast cancer

Characteristics

n

expression of HMGA1 in breast cancer tissues (Intensity score = 1). c Strong staining of HMGA1 in breast cancer tissues (Intensity score = 3)

High expression (%)

Low expression (%)

P

Age (years) \50

60

38 (63.3)

22 (36.7)

C50

92

47 (51.1)

45 (48.9)

I

53

23 (43.4)

30 (56.6)

II–III

99

62 (62.6)

37 (37.4)

I–II

55

23 (30.8)

32 (58.2)

III–IV

97

62 (63.9)

35 (36.1)

T1–T2

90

43 (47.8)

47 (52.2)

T3–T4

62

42 (67.7)

20 (32.3)

N0–N1

69

29 (42.0)

40 (58.0)

N2–N3

83

56 (67.5)

27 (32.5)

138

71 (51.4)

67 (48.6)

14

14 (100)

0.137

Histological grade 0.023

Clinical stage 0.008

Tumor size 0.015

Lymph node metastasis

Distant metastasis M0 M1

0.002

\0.001

0 (0)

Triple-negative breast cancer No

120

61 (50.8)

59 (49.2)

Yes

32

24 (75.0)

8 (25.0)

transition, and maintenance of stemness [4, 5]. HMGA1 oncogene is widely expressed during embryogenesis and oncogenesis, and is low or almost absent in the differentiated tissues in adults [4]. In breast cancer, HMGA1 protein overexpression was significantly with the metastatic phenotype of human breast cancer cell lines [13]. Furthermore, recent study showed that interfering with HMGA1 expression reduced the tumorigenic and

123

0.014

metastatic potential of breast cancer cells in vivo [25]. HMGA1 activity is not restricted to regulation of cell proliferation and mobility and is necessary for several processes involved in induction of epithelial-mesenchymal transition and pluripotent stem cells. In basal-like breast cancer subtype, Pegoraro et al. indicated that HMGA1 was fundamental in sustaining stem cell and metastatic properties through cooperating with the Wnt/beta-catenin and

Mol Cell Biochem

Fig. 3 Increased HMGA1 protein expression predicts an unfavorable prognosis (Low expression: final staining scores = 0–4; High expression final staining scores = 5–7). The association between patient survival and HMGA1 expression was estimated using the Kaplan–Meier method and the log-rank test (P \ 0.001)

Pin1/mutant p53 signaling pathways [14]. Moreover, Shah et al. reported that HMGA1 is a master regulator of tumor progression in breast cancer by reprogramming cancer cells through stem cell transcriptional networks in triple-negative breast cancer cells [15]. As for HMGA1 expression in breast cancer, most studies published so far have been performed on cell lines. However, little is known about the accurate pathological role of HMGA1 in breast cancer patients. The aim of our study was to identify whether HMGA1 protein might be an indicator for the diagnosis and prognosis in breast cancer. Increased expression of HMGA1 was observed in several types of human cancer. In our study, we verify mRNA and protein expression levels of HMGA1 were higher in breast cancer tissues than those in adjacent normal tissues, which was consistent with Liu et al. study in breast cancer

cell lines [13] and Chiappetta et al. study in breast cancer tissues [10]. Moreover, we further identified the role of HMGA1 in the development and progression of breast cancer. We analyzed the expression of HMGA1 in breast cancer patients and found HMGA1 overexpression was positively correlated with clinical stage, tumor size, lymph node metastasis, distant metastasis, histological grade, and triple-negative breast cancer subtype. Overexpressed HMGA1 in breast cancer may accelerate tumor growth, enhance local cell invasion and metastasis, and regulate cell differentiation. Similar to Wang et al. report, HMGA1 expression also correlated with tumor size, tumor invasion, and histological grade in human pituitary adenomas [26]. In laryngeal squamous cell carcinoma, HMGA1 overexpression positively associated with clinical stage, lymph node metastasis, and histological grade [27]. These studies consistently suggest that overexpressed HMGA1 may play an unfavorable role in breast cancer patients. Although the association between HMGA1 expression and OS was evaluated in patients with lung cancer [16], colorectal cancer [17], liver cancer [18], pancreatic adenocarcinoma [19–21], and uveal melanomas [22], the association between HMGA1 expression and the survival of breast cancer patients has been seldomly reported. In this study, we showed that HMGA1 expression in breast cancer was inversely correlated with patient’s OS. The patients with higher expression of HMGA1 protein had shorter survival time. According to multivariate analyses, overexpression of HMGA1 protein was a significant predictor of poor prognosis for breast cancer patients. These results were consistent to Takahashi et al. report, which suggested that increased expression of HMGA1 significantly correlated with clinical stage and lymph node metastasis, and as an independent biomarker for poor prognosis of colorectal cancer patients [17]. Similarly, Liau et al. reported HMGA1 expression was predictive of poor patient survival and was an independent prognostic indicator in pancreatic cancer [21].

Table 2 Univariate and multivariate Cox regression analyses of overall survival Parameters

Univariate analysis HR

95 % CI

Multivariate analysis P

HR

Age (\50 vs. C50)

1.040

0.717–1.508

0.837

Histological grade (I vs. II–III)

1.423

0.963–2.104

0.077

95 % CI

P

Clinical stage (I–II vs. III–IV)

3.946

2.522–6.172

\0.001

2.331

1.105–4.919

Tumor size (T1–T2 vs. T3–T4)

2.398

1.644–3.495

\0.001

1.817

0.737–3.131

0.006

Lymph node metastasis (N0–N1 vs. N2–N3)

3.776

2.424–5.882

\0.001

1.519

0.737–3.131

0.258

10.112

5.017–20.384

\0.001

4.200

2.004–8.802

\0.001

1.597 2.416

1.051–2.425 1.642–3.554

0.028 \0.001

1.129 1.691

0.709–1.798 1.118–2.558

0.609 0.013

Distant metastasis (M0 vs. M1) Triple-negative breast cancer (no vs. yes) HMGA1 (low vs. high)

0.026

HR hazard ratio; 95 % CI 95 % confidence interval

123

Mol Cell Biochem

In summary, our study showed that the mRNA and protein expression level of HMGA1 was significantly increased in breast cancer tissues and associated with the malignant status of breast cancer. Moreover, our results indicated that HMGA1 was a significant prognostic factor for breast cancer patients. Because of the limited patient sample size in our study, further studies are needed to strengthen these findings and evaluate the role of HMGA1 as a reliable clinical predictor of outcome for breast cancer patients. Acknowledgments This study was supported by the Central South University Postdoctoral Funding (No. 149938) and Open-End Fund for the Valuable and Precision Instruments of Central South University (CSUZC201537). Conflict of interest

None.

References 1. Siegel R, Ma J, Zou Z, Jemal A (2014) Cancer statistics, 2014. CA Cancer J Clin 64(1):9–29. doi:10.3322/caac.21208 2. Hortobagyi GN, de la Garza Salazar J, Pritchard K, Amadori D, Haidinger R, Hudis CA, Khaled H, Liu MC, Martin M, Namer M, O’Shaughnessy JA, Shen ZZ, Albain KS (2005) The global breast cancer burden: variations in epidemiology and survival. Clin Breast Cancer 6(5):391–401 3. Cowin P, Rowlands TM, Hatsell SJ (2005) Cadherins and castenins in breast cancer. Curr Opin Cell Biol 17(5):499–508. doi:10.1016/j.ceb.2005.08.014 4. Shah SN, Resar LM (2012) High mobility group A1 and cancer: potential biomarker and therapeutic target. Histol Histopathol 27(5):567–579 5. Cleynen I, Van de Ven WJ (2008) The HMGA proteins: a myriad of functions (Review). Int J Oncol 32(2):289–305 6. Pogna EA, Clayton AL, Mahadevan LC (2010) Signalling to chromatin through post-translational modifications of HMGN. Biochim Biophys Acta 1799(1–2):93–100. doi:10.1016/j.bbagrm. 2009.11.018 7. Tamimi Y, van der Poel HG, Denyn MM, Umbas R, Karthaus HF, Debruyne FM, Schalken JA (1993) Increased expression of high mobility group protein I(Y) in high grade prostatic cancer determined by in situ hybridization. Cancer Res 53(22):5512–5516 8. Tamimi Y, van der Poel HG, Karthaus HF, Debruyne FM, Schalken JA (1996) A retrospective study of high mobility group protein I(Y) as progression marker for prostate cancer determined by in situ hybridization. Br J Cancer 74(4):573–578 9. Fedele M, Bandiera A, Chiappetta G, Battista S, Viglietto G, Manfioletti G, Casamassimi A, Santoro M, Giancotti V, Fusco A (1996) Human colorectal carcinomas express high levels of high mobility group HMGI(Y) proteins. Cancer Res 56(8):1896–1901 10. Chiappetta G, Botti G, Monaco M, Pasquinelli R, Pentimalli F, Di Bonito M, D’Aiuto G, Fedele M, Iuliano R, Palmieri EA, Pierantoni GM, Giancotti V, Fusco A (2004) HMGA1 protein overexpression in human breast carcinomas: correlation with ErbB2 expression. Clin Cancer Res 10(22):7637–7644. doi:10. 1158/1078-0432.ccr-04-0291 11. Abe N, Watanabe T, Masaki T, Mori T, Sugiyama M, Uchimura H, Fujioka Y, Chiappetta G, Fusco A, Atomi Y (2000) Pancreatic duct cell carcinomas express high levels of high mobility group I(Y) proteins. Cancer Res 60(12):3117–3122

123

12. Masciullo V, Baldassarre G, Pentimalli F, Berlingieri MT, Boccia A, Chiappetta G, Palazzo J, Manfioletti G, Giancotti V, Viglietto G, Scambia G, Fusco A (2003) HMGA1 protein over-expression is a frequent feature of epithelial ovarian carcinomas. Carcinogenesis 24(7):1191–1198. doi:10.1093/carcin/bgg075 13. Liu WM, Guerra-Vladusic FK, Kurakata S, Lupu R, KohwiShigematsu T (1999) HMG-I(Y) recognizes base-unpairing regions of matrix attachment sequences and its increased expression is directly linked to metastatic breast cancer phenotype. Cancer Res 59(22):5695–5703 14. Pegoraro S, Ros G, Piazza S, Sommaggio R, Ciani Y, Rosato A, Sgarra R, Del Sal G, Manfioletti G (2013) HMGA1 promotes metastatic processes in basal-like breast cancer regulating EMT and stemness. Oncotarget 4(8):1293–1308 15. Shah SN, Cope L, Poh W, Belton A, Roy S, Talbot CC Jr, Sukumar S, Huso DL, Resar LM (2013) HMGA1: a master regulator of tumor progression in triple-negative breast cancer cells. PLoS One 8(5):e63419. doi:10.1371/journal.pone.0063419 16. Sarhadi VK, Wikman H, Salmenkivi K, Kuosma E, Sioris T, Salo J, Karjalainen A, Knuutila S, Anttila S (2006) Increased expression of high mobility group A proteins in lung cancer. J Pathol 209(2):206–212. doi:10.1002/path.1960 17. Takahashi Y, Sawada G, Sato T, Kurashige J, Mima K, Matsumura T, Uchi R, Ueo H, Ishibashi M, Takano Y, Akiyoshi S, Eguchi H, Sudo T, Sugimachi K, Tanaka J, Kudo SE, Doki Y, Mori M, Mimori K (2013) Microarray analysis reveals that high mobility group A1 is involved in colorectal cancer metastasis. Oncol Rep 30(3):1488–1496. doi:10.3892/or.2013.2602 18. Chang ZG, Yang LY, Wang W, Peng JX, Huang GW, Tao YM, Ding X (2005) Determination of high mobility group A1 (HMGA1) expression in hepatocellular carcinoma: a potential prognostic marker. Dig Dis Sci 50(10):1764–1770. doi:10.1007/ s10620-005-2934-9 19. van der Zee JA, ten Hagen TL, Hop WC, van Dekken H, Dicheva BM, Seynhaeve AL, Koning GA, Eggermont AM, van Eijck CH (2010) Differential expression and prognostic value of HMGA1 in pancreatic head and periampullary cancer. Eur J Cancer 46(18):3393–3399. doi:10.1016/j.ejca.2010.07.024 20. Hristov AC, Cope L, Di Cello F, Reyes MD, Singh M, Hillion JA, Belton A, Joseph B, Schuldenfrei A, Iacobuzio-Donahue CA, Maitra A, Resar LM (2010) HMGA1 correlates with advanced tumor grade and decreased survival in pancreatic ductal adenocarcinoma. Mod Pathol 23(1):98–104. doi:10.1038/modpathol. 2009.139 21. Liau SS, Whang E (2009) High mobility group A: a novel biomarker and therapeutic target in pancreatic adenocarcinoma. Surgeon 7(5):297–306 22. Qu Y, Wang Y, Ma J, Zhang Y, Meng N, Li H, Wang Y, Wei W (2013) Overexpression of high mobility group A1 protein in human uveal melanomas: implication for prognosis. PLoS One 8(7):e68724. doi:10.1371/journal.pone.0068724 23. Liu Z, Li X, He X, Jiang Q, Xie S, Yu X, Zhen Y, Xiao G, Yao K, Fang W (2011) Decreased expression of updated NESG1 in nasopharyngeal carcinoma: its potential role and preliminarily functional mechanism. Int J Cancer 128(11):2562–2571. doi:10. 1002/ijc.25595 24. Zhen Y, Liu Z, Yang H, Yu X, Wu Q, Hua S, Long X, Jiang Q, Song Y, Cheng C, Wang H, Zhao M, Fu Q, Lyu X, Chen Y, Fan Y, Liu Y, Li X, Fang W (2013) Tumor suppressor PDCD4 modulates miR-184-mediated direct suppression of C-MYC and BCL2 blocking cell growth and survival in nasopharyngeal carcinoma. Cell Death Dis 4:e872. doi:10.1038/cddis.2013.376 25. Di Cello F, Shin J, Harbom K, Brayton C (2013) Knockdown of HMGA1 inhibits human breast cancer cell growth and metastasis

Mol Cell Biochem in immunodeficient mice. Biochem Biophys Res Commun 434(1):70–74. doi:10.1016/j.bbrc.2013.03.064 26. Wang EL, Qian ZR, Rahman MM, Yoshimoto K, Yamada S, Kudo E, Sano T (2010) Increased expression of HMGA1 correlates with tumour invasiveness and proliferation in human

pituitary adenomas. Histopathology 56(4):501–509. doi:10.1111/ j.1365-2559.2010.03495.x 27. Wang DS, Pan CC, Lai HC, Huang JM (2013) Expression of HMGA1 and ezrin in laryngeal squamous cell carcinoma. Acta Otolaryngol 133(6):626–632. doi:10.3109/00016489.2012.758388

123