FOXA1 levels are decreased in pleural breast cancer metastases after adjuvant endocrine therapy, and this is associated with poor outcome.
Estrogen receptor-alpha (ERα)-positive breast cancer is often treated with antihormonal regimens. However, resistance to treatment is common, leading to metastatic disease. ERα activity requires the functional involvement of pioneer factors FOXA1 and GATA3, which enable ERα-chromatin binding and are crucial for ERα-driven cell proliferation. FOXA1 was found increased in metastatic breast cancers in relation to the primary tumor, but a comprehensive clinical assessment thereof, in relation to different metastatic sites and endocrine therapy usage, is currently lacking. Prior cell line-based reports, however, have revealed that FOXA1 is required for tamoxifen-resistant tumor cell proliferation. We studied expression levels of ERα, GATA3, and FOXA1 by immunohistochemistry in samples from both primary tumors and various metastatic sites. For all factors, expression levels varied between the metastatic sites. For pleural metastases, strong variation was found in FOXA1 and GATA3 levels. Although GATA3 levels remained unaltered between primary breast cancer and pleural metastases, FOXA1 levels were reduced exclusively in metastases of patients who received endocrine therapies in the adjuvant setting, even though ERα was still expressed. Importantly, decreased FOXA1 levels in pleural metastases correlated with hormone irresponsiveness in the palliative setting, while no such correlation was found for GATA3. With this, we show divergent clinical correlations of the two ERα pioneer factors FOXA1 and GATA3 in metastatic breast cancer, where endocrine therapy resistance was associated with decreased FOXA1 levels in pleural metastases.
['Schrijver|Willemijne|W|', 'Schuurman|Karianne|K|', 'van Rossum|Annelot|A|', 'Droog|Marjolein|M|', 'Jeronimo|Carmen|C|', 'Salta|Sofia|S|', 'Henrique|Rui|R|', 'Wesseling|Jelle|J|', 'Moelans|Cathy|C|', 'Linn|Sabine C|SC|', 'van den Heuvel|Michel|M|', 'van Diest|Paul|P|', 'Zwart|Wilbert|W|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D001943:Breast Neoplasms D017024:Chemotherapy, Adjuvant D018572:Disease-Free Survival D005260:Female D051541:Hepatocyte Nuclear Factor 3-alpha D006801:Humans D008297:Male D008875:Middle Aged D009362:Neoplasm Metastasis D009363:Neoplasm Proteins D010997:Pleural Neoplasms D015996:Survival Rate
FOXA1 GATA3 acquired endocrine resistance breast cancer metastasis pleural effusions