FISH and immunohistochemical status of the hepatocyte growth factor receptor (c-Met) in 184 invasive breast tumors

  • Alma Carracedo1, 2, 3,

    Affiliated with

    • Kristof Egervari4,

      Affiliated with

      • Marta Salido1, 3,

        Affiliated with

        • Federico Rojo5, 6, 7,

          Affiliated with

          • Josep M Corominas5,

            Affiliated with

            • Montserrat Arumi5, 6, 8,

              Affiliated with

              • Cristina Corzo9,

                Affiliated with

                • Ignacio Tusquets10,

                  Affiliated with

                  • Blanca Espinet1, 3,

                    Affiliated with

                    • Ana Rovira6,

                      Affiliated with

                      • Joan Albanell6, 10,

                        Affiliated with

                        • Zoltan Szollosi4,

                          Affiliated with

                          • Sergi Serrano5 and

                            Affiliated with

                            • Francesc Solé1, 3Email author

                              Affiliated with

                              Breast Cancer Research200911:402

                              DOI: 10.1186/bcr2239

                              Published: 21 April 2009

                              In their report, Götte and coworkers [1] analyzed the expression of c-Met in 200 patients with ductal carcinoma in situ. They concluded that c-Met could be related to angiogenic and lymphangiogenic factors in ductal carcinoma in situ. On the other hand, Greenberg and coworkers [2] studied 31 patients with ductal infiltrating carcinoma (DIC) to detect c-Met expression in their axillary fluids. They observed a correlation of c-Met expression with increasing tumor size and grade, capillary and lymphatic invasion and lymph node metastasis.

                              We applied the fluorescent in situ hybridization (FISH) technique using the LSI D7S486/CEP7 commercial probe (Abbott Molecular Inc., Des Plaines, IL, USA), which includes the MET gene, and immunohistochemistry using c-Met monoclonal antibody clone 3D4 (Invitrogen, Carlsbad, CA, USA) to 184 archival invasive breast tumors (93 DIC and 91 lobular carcinomas). We constructed ten tissue microarrays with three replicates per sample. Pearson's chi-squared and Fisher's exact test were used to analyze the results.

                              None of the 155 breast tumors analyzed by FISH presented amplification of MET and 35 cases (22%) had a low grade of polysomy (three to five copies) of chromosome 7. Polysomy was more frequently observed in DIC (25%; P = 0.001). We tried to correlate polysomy of MET in the DIC group with grade, tumor size, lymph node status, clinical stage and expression of HER2, P53, estrogen receptor (ER) and progesterone receptor (PR). We observed that the absence of expression of PR was the unique statistically significant variable (P = 0.001). Moreover, the ER+/PR- samples presented the highest rate of polysomy (38%) compared to ER+/PR+ tumors (15%) (Table 1).
                              Table 1

                              Results of IHC of c-Met and FISH of LSI D7S486/CEP7 applied to lobular and ductal carcinomas

                               

                              IHC c-Met

                              FISH MET

                              FISH + IHC

                               

                              Negative

                              Positive

                              Negative

                              Polysomy

                              PE + P

                              Carcinoma type

                                   

                                 Lobular

                              57 (76%)

                              18 (24%)

                              61 (81%)

                              15 (19%)

                              5 (7%)

                                 Ductal (DIC)

                              42 (52%)

                              38 (48%)

                              60 (75%)

                              20 (25%)

                              13 (16%)

                              DIC type

                                   

                                 ER+/PR+

                              31 (68%)

                              15 (32%)

                              39 (85%)

                              7 (15%)

                              3 (6%)

                                 ER+/PR-

                              11 (32%)

                              23 (68%)

                              21 (62%)

                              13 (38%)

                              10 (29%)

                              DIC, ductal infiltrating carcinoma; PE, positive expression; ER, estrogen receptor; FISH, fluorescent in situ hybridization; IHC, immunohistochemistry; P, polysomy; PR, progesterone receptor. In bold we remark the positive FISH and IHQ results for DIC as well as for ER+/PR- tumors

                              Out of 168 tumors analyzed by immunohistochemistry, 65 (38.7%) presented expression of c-Met. When histological types were compared, the DIC group also showed the highest number of c-Met-positive samples (48%; P = 0.001). From the analysis with the clinico-pathological variables, the negativity for PR was again statistically significant (P = 0.001). The ER+/PR- tumors presented more frequent expression of c-Met (68%) compared to ER+/PR+ tumors (32%) and were correlated with polysomy (P = 0.020) (Table 2).
                              Table 2

                              IHC and FISH results of MET according to the status of PR receptor in DIC carcinomas

                               

                              ER+/PR+ (n = 46)

                              ER+/PR- (n = 34)

                               

                              IHC

                              IHC

                              IHC

                              IHC

                              FISH MET

                              Negative

                              Positive

                              Negative

                              Positive

                              FISH Negative

                              27 (59%)

                              12 (26%)

                              9 (23%)

                              13 (38%)

                              FISH Polysomy

                              4 (9%)

                              3 (6%)

                              3 (9%)

                              10 (29%)

                              DIC, ductal infiltrating carcinoma; ER, estrogen receptor; FISH, fluorescent in situ hybridization; IHC, immunohistochemistry; P, polysomy; PR, progesterone receptor. In bold we remark the FISH and IHQ positive results to compare both groups.

                              We can conclude that amplification of MET in breast cancer is not a common event, as opposed to other cancer subtypes (renal, gastric and lung carcinomas). Although found in breast tumors, it seems that overexpression of c-Met is not mainly due to increassed gene copy number of MET/polysomy7. However, polysomy in the ER+/PR- group could be an important mechanism – although not the only one – responsible for the differential expression observed in this type of DIC. This c-Met overexpression and the presence of polysomy 7 could be important events to be considered with regard to the known poor response to endocrine therapies of ER+/PR- breast tumors. Lack of PR expression in ER+ tumors may be a surrogate marker of aberrant growth factor signaling [3] that could be associated with their more aggressive outcome, as has already been described [4].

                              Our study suggests that it would be interesting to investigate new therapeutic options for ER+/PR- DIC, which may include c-Met inhibitors.

                              Abbreviations

                              DIC: 

                              ductal infiltrating carcinoma

                              ER: 

                              estrogen receptor

                              FISH: 

                              fluorescent in situ hybridization

                              PR: 

                              progesterone receptor

                              Declarations

                              Acknowledgements

                              Grants PI05/0961 and PI06/1513 from Ministerio de Sanidad y Consumo ISCIII and RTICC 06/0020/19. Tumoral samples belong to the 'Xarxa de Banc de Tumors de Catalunya' (XBTC).

                              Authors’ Affiliations

                              (1)
                              Servei de Patologia, Laboratori de Citogenètica Molecular, Hospital del Mar, IMAS, GRETNHE, IMIM
                              (2)
                              Departament de Biologia Cellular, Universitat Autònoma de Barcelona
                              (3)
                              Escola de Citologia Hematològica S Woessner-IMAS
                              (4)
                              Department of Pathology, University of Debrecen MHSC
                              (5)
                              Servei de Patologia, Unitat de Patologia Mamària, Hospital del Mar, UAB
                              (6)
                              Molecular Therapeutics and Biomarkers in Breast Cancer Program, IMIM-Hospital del Mar
                              (7)
                              Capio-Fundación Jiménez Díaz
                              (8)
                              Department of Health and Experimental Sciences, Universitat Pompeu Fabra
                              (9)
                              Escola Bonanova-IMAS
                              (10)
                              Oncology Department, Hospital del Mar

                              References

                              1. Götte M, Kersting C, Radke I, Kiesel L, Wülfing P: An expression signature of syndecan-1 (CD138), E-cadherin and c-met is associated with factors of angiogenesis and lymphangiogenesis in ductal breast carcinoma in situ . Breast Cancer Res 2007, 9:R8.View ArticlePubMed
                              2. Greenberg R, Schawartz I, Skornick Y, Kaplan O: Detection of hepatocyte growth factor/scatter factor repector (c-Met) in axillary drainage after operations for breast cancer using reverse transcriptase-polymerase chain reaction. Breast Cancer Res 2003, 5:R71-R76.View ArticlePubMed
                              3. Creighton CJ, Osborne K, Vijver MJ, Foekens JA, Klin JG, Horlings HM, Nuyten D, Wang Y, Zhang Y, Chammess GC, Hilsenbeck SG, Lee AV, Schiff R: Molecular profiles of progesterone receptor loss in human breast tumors. Breast Cancer Res Treat 2009, 114:287–299.View ArticlePubMed
                              4. Arpino G, Weiss H, Lee VA, Schiff R, De Placido S, Osborne K, Elledge RM: Estrogen receptor-positive, progesterone receptor-negative breast cancer; association with growth factor receptor expression and tamoxifen resistance. J Natl Cancer Inst 2005, 97:1254–1261.View ArticlePubMed

                              Copyright

                              © BioMed Central Ltd 2009

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