Clinical significance of immunohistochemistry for detection of BAP1mutations in uveal melanoma

Autor: Koopmans, Anna E, Verdijk, Robert M, Brouwer, Rutger W W, van den Bosch, Thierry P P, van den Berg, Mike M P, Vaarwater, Jolanda, Kockx, Christel E M, Paridaens, Dion, Naus, Nicole C, Nellist, Mark, van IJcken, Wilfred F J, Kiliç, Emine, de Klein, Annelies
Zdroj: Modern Pathology; October 2014, Vol. 27 Issue: 10 p1321-1330, 10p
Abstrakt: Uveal melanoma is a lethal cancer with a strong propensity to metastasize. Limited therapeutic options are available once the disease has disseminated. A strong predictor for metastasis is the loss of chromosome 3. Inactivating mutations in BAP1encoding the BRCA1-associated protein 1 and located on chromosome 3p21.1, have been described in uveal melanoma and other types of cancer. In this study, we determined the prevalence of somatic BAP1mutations and examined whether these mutations correlate with the functional expression of BAP1 in uveal melanoma tissue and with other clinical, histopathological and chromosomal parameters. We screened a cohort of 74 uveal melanomas for BAP1mutations, using different deep sequencing methods. The frequency of BAP1mutations in our study group was 47%. The expression of BAP1 protein was studied using immunohistochemistry. BAP1 staining was absent in 43% of the cases. BAP1mutation status was strongly associated with BAP1 protein expression (P<0.001), loss of chromosome 3 (P<0.001), and other aggressive prognostic factors. Patients with a BAP1mutation and absent BAP1 expression had an almost eightfold higher chance of developing metastases compared with those without these changes (P=0.002). We found a strong correlation between the immunohistochemical and sequencing data and therefore propose that, immunohistochemical screening for BAP1 should become routine in the histopathological work-up of uveal melanoma. Furthermore, our analysis indicates that loss of BAP1 may be particularly involved in the progression of uveal melanoma to an aggressive, metastatic phenotype.
Databáze: Supplemental Index