Abstract
BackgroundBreast cancer clinical management requires the assessment of hormone receptors (estrogen (ER) and progesterone receptor (PR)), human epidermal growth factor receptor 2 (HER2) and cellular proliferation index Ki67, by immunohistochemistry (IHC), in order to choose and guide therapy according to tumor biology. Many studies have reported contradictory results regarding changes in the biomarker profile after neoadjuvant therapy (NAT). Given its clinical implications for the disease management, we aimed to analyze changes in ER, PR, HER2, and Ki67 expression in paired core-needle biopsies and surgical samples in breast cancer patients that had either been treated or not with NAT.MethodsWe included 139 patients with confirmed diagnosis of invasive ductal breast carcinoma from the Colombian National Cancer Institute. Variation in biomarker profile were assessed according to NAT administration (NAT and no-NAT treated cases) and NAT scheme (hormonal, cytotoxic, cytotoxic + trastuzumab, combined). Chi-squared and Wilcoxon signed-rank test were used to identify changes in biomarker status and percentage expression, respectively, in the corresponding groups.ResultsWe did not find any significant variations in biomarker status or expression values in the no-NAT group. In cases previously treated with NAT, we did find a statistically significant decrease in Ki67 (p < 0.001) and PR (p = 0.02605) expression. When changes were evaluated according to NAT scheme, we found a significant decrease in both Ki67 status (p = 0.02977) and its expression values (p < 0.001) in cases that received the cytotoxic treatment.ConclusionsOur results suggest that PR and Ki67 expression can be altered by NAT administration, whereas cases not previously treated with NAT do not present IHC biomarker profile variations. The re-evaluation of these two biomarkers after NAT could provide valuable information regarding treatment response and prognosis for breast cancer patients.
Highlights
Breast cancer clinical management requires the assessment of hormone receptors (estrogen (ER) and progesterone receptor (PR)), human epidermal growth factor receptor 2 (HER2) and cellular proliferation index Ki67, by immunohistochemistry (IHC), in order to choose and guide therapy according to tumor biology
All tumors were classified as Invasive ductal carcinoma (IDC), of which the majority presented a clinical stage of III (49.6%) and a Scarff-Bloom-Richardson score of II (59.7%)
In order to assess the impact of neoadjuvant therapy (NAT) treatment in biomarker status and its expression values, we performed an analysis in paired samples stratified by NAT administration
Summary
Breast cancer clinical management requires the assessment of hormone receptors (estrogen (ER) and progesterone receptor (PR)), human epidermal growth factor receptor 2 (HER2) and cellular proliferation index Ki67, by immunohistochemistry (IHC), in order to choose and guide therapy according to tumor biology. (IHC) of biomarkers, such as: hormone receptors (estrogen receptor (ER) and progesterone receptor (PR)), human epidermal growth factor receptor 2 (HER2) and the cellular proliferation index (Ki67), is analyzed to guide the therapy and predict survival [4, 6, 7]. These biomarkers have been used as surrogates for breast cancer classification into four main intrinsic subtypes: luminal A, luminal B, HER2-enriched and triple negative (TN) [8]. Luminal A and luminal B tumors express ER, these patients are candidates for hormone therapy with ER modulators or aromatase inhibitors [8–11], whilst HER2-enriched and TN subtypes lack the expression of hormone receptors, are mainly treated with biological therapy agents such as trastuzumab or pertuzumab, and cytotoxic chemotherapy, respectively [5, 11, 12]
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