3855991747

Oncogene (2007) 26. 298 307

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ONCOGENOMICS

Correlated break at PARK2/FRA6E and loss of AF-6/Afadin protein expression are associated with poor outcome in breast cancer

A Letessier^1,7, S Garrido-Urbani²-⁷, C Ginestier¹, G Fournier², B Esterni^3,4, F Momille¹, J Adelaide¹, J Geneix‘, L Xerri⁵-⁶, P Dubreuil², P Viens⁴-⁶, E Charafe-Jauffret¹*⁵-⁶,

J Jaccjuemier¹⁵, D Birnbaum¹, M Lopez² and M Chaffanel¹ 'Centrę de Recherche en Canceroloyie de Marseille, Departement dOncoloyie Moleculaire, UMR599 Inserm et Insi i tut Paoli-Calmettes, Marseille, France; ‘Hematopoiese Fonctionnelle et Moleculaire. UMR5 99 Insertu et Insi ilu t Paoli-Calmettes. Marseille. France:³Departement de Pioslatistigues. Institut Paoli-Calmettes. Marseille. France;⁴Departement dOncoloyie Medicale. UMR599 Inserm et Institut Paoli-Calmettes. Marseille. France;^fDepartement de BioPathologie. Institut Paoli-Calmettes, Marseille, France and ⁶Faculte de Medecine. Unii ersile de la Mediterranee. Marseille. France

( ommon Ir agile sites (CFSs) are regions of chroniosomal break that may play a role in oneogenesis. The most frequent alteration occurs at FRA3B. within the FIUT gene, at chromosomal region 3p 14. We studied a series of breast carcinomas for break of a CFS at 6q26, FRA6E, and its associated gene PARK2. using (luorescence in situ hvbridi/ation on tissue niicroarrays (TMA). We found break of PARK2 in 6% of cases. We studied the PARK2-encoded protein Parkin In using imniunohistochemistry on the same TM A. Loss of Parkin was found in 13% of saniples but was not correlated with PARK2 break. PARK2 break but not Parkin e.\|)ression was correlated with prognosis. Alteration of PARK2/FRA6E may cause haplo-insufliciency of one or several telonieric potential tumor suppressor genes (TSG). The AF-6/MLLT4 gene. telonieric of PARK2. encodes the Afadin scaffold protein, which is essential for epithelial integrity. Loss of Afadin was found in 14.5% of cases. and 36% of these cases showed PARK2 break. Loss of Afadin had prognostic impact. suggesting that AF-6 may be a TSG. Loss of Afadin was correlated with loss of FIUT e\pression. suggesting fragility of FRA6E and FRA3R in a certain proportion of breast tumors.

Oncogene (2007) 26. 298 307. doi: 10.1038/sj.onc. 1209772; published online 3 July 2006

Keywords: Afadin; AF-6 gene; breast cancer; FRA6F; Parkin; PARK2 gene; tissue niicroarrays

Introduction

The human chromosomes contain scveral regions called fragile sites that are particularly susceptible to break in response to environmental carcinogens (Richards,

Corrcspondence: Dr D Birnbaum. UMR599 Inserm. 27 Bd. Lei Roure. 13009 Marseille. brance.

E-mail: birnbaum (a marseille.inscrm.fr These authors contributed equally to this work.

Received 21 Decem ber 2(K)5; rcvised 27 April 2006; acccptcd 22 May 2(K)6; published online 3 July 2006

2001). Breaks at common fragile sites (CFS) may play a role in tumor initiation and/or progression (Huebner and Croce, 2001; Dhillon et    al.,

2003; Popescu, 2003). Among them. the most frequently altered CFSs, FRA3B at 3pl4.2 and FRAI6D at 16q23.3, are encompassed by FIUT (Fragile Histidine Triad) and WWOX (WW domain-containing oxydo-reductase) loci. respectively (Huebner et al.. 1998; Bednarek et al., 2000). FIUT and WWOX are both considered as tumor suppressor genes (TSG) (Bednarek et a/.. 2001; Paige et al.. 2001; Huebner and Croce. 2003; Fabbri et al.. 2005). Their alterations are found in various types of cancer and lead to the loss or inactivation of their respective protcins (Paige et a/.. 2001; Huebner and Croce. 2003). We have previously reported that the loss of FHIT cxpression is a marker of adverse evolution in good prognosis localized breast cancer (Ginestier et a/., 2003). FIUT and WWOX are coordinately inactivated in a subset of invasive breast cancers (Guler et a/.. 2005).

The third most frequent CFS, FRA6E, is located in chromosomc region 6q26 within approximately 3.6 Mb. The PARK2 gene encompasses the distal half of the FRA6E locus. The most unstable region of FRA6E is localized betwecn exons 2 and 8 of PARK2. The PA RK2 gene encodes Parkin, a cytoplasmic E3 ubiquitin protein ligase, whose mutations cause autosomal-recessive juvcnilc Parkinsonism (Kitada et al.. 1998; Marin et al.. 2004). Frequent loss of heterozygosity (LOH) in introns 2 and 6 and downregulation of Parkin are found in ovarian tumors (Cesari et al.. 2003; Dcnison et a!.. 2003b; Picchio et al.. 2004; Wang et al., 2004), which suggests that PARK2 may be involved in oneogenesis as a TSG.

The long arm of chromosome 6 contains potential TSG involved in various types of cancer such as melanoma (Millikin et al.. 1991), ovarian carcinoma (Saito et al., 1992; Tibiletti et al.. 1996), breast carcinoma (Orphanos et al.. 1995; Noviello et al.. 1996), non-Hodgkin's lymphoma (Menasce et al., 1994a) and acutc leukemia (Hayashi et al., 1990; Menasce et al., 1994b). Tumorigenicity of breast celi