Angela Santonja

The seed and soil hypothesis revisited: Current state of knowledge of inherited genes on prognosis in breast cancer

The crucial event in the course of malignancies such as breast cancer is its metastatic spread from the primary tumor of origin to distant organs. The natural history of a tumor is determined by the expression of its genes, and in this sense, knowledge has advanced dramatically in recent decades. However, much less is known about the role that the patient plays in the behavior of a tumor. In this article, we review the evidence regarding the genetic background of the host in metastatic tumor dissemination, providing information from epidemiological studies as well as from animal models and human studies. Undoubtedly, the elucidation of possible interpersonal variability in susceptibility to developing metastases would significantly contribute to improve management of cancer patients.

Proliferation Determined by Ki-67 Defines Different Pathologic Response to Neoadjuvant Trastuzumab-Based Chemotherapy in HER2-Positive Breast Cancer

BACKGROUND This study aimed to assess the role of proliferation measured by Ki-67 as a predictive factor for pathologic complete response (pCR) to trastuzumab-based chemotherapy in patients with human epidermal growth factor receptor 2 (HER2)-positive (HER2(+)) breast cancer (BC). METHODS A total of 81 patients with HER2(+) BC were treated with a sequential schedule consisting of 4 cycles of cyclophosphamide (600 mg/m(2)) and doxorubicin (60 mg/m(2)) every 3 weeks, followed by 4 cycles of weekly paclitaxel (80 mg/m(2)) or docetaxel (100 mg/m(2)) every 3 weeks combined with trastuzumab (loading dose of 8 mg/kg and then 6 mg/kg every 3 weeks) as neoadjuvant treatment. Histologic subgroups classified by hormone receptor (HR) expression and Ki-67 index were 17% HR(+)/Ki-67 ≥ 50%, 41% HR(+)/Ki-67 < 50%, 25% HR-negative (HR(-)) Ki-67 ≥ 50%, and 17% HR(-)/Ki-67 < 50%. RESULTS pCR, defined as the absence of invasive cells in the breast and axillary lymph node, was achieved in 33 patients (41%). The median Ki-67 expression was significantly higher in tumors with pCR (53%) compared with tumors without pCR (30%) (P < .001). Receiver operating characteristic (ROC) curve methodology suggested that 50% was the optimal Ki-67 cutoff point to best identify patients who achieved a pCR. The pCR rate was significantly different between histologic subgroups: HR(-)/Ki-67 ≥ 50% (70%), HR(+)/Ki-67 ≥ 50% (71%), HR(-)/Ki-67 < 50% (22%), and HR(+)/Ki-67 < 50% (18%) (P < .001). A multivariate analysis revealed that a Ki-67 marker ≥ 50% was the only independent predictive factor of pCR (P = .003; odds ratio [OR], 0.133; 95% confidence interval [CI], 0.036-0.5). The median follow-up was 32 months (range, 14-48 months). Patients who achieved a pCR had significantly lower recurrence (P = .001) and higher overall survival (OS) (P = .013) compared with those who did not. There were no statistically significant differences in disease-free survival (DFS) and OS in relation to HRs, the Ki-67 marker as a continuous or categorical variable, and histologic subgroups. CONCLUSION Proliferation determined by Ki-67 expression ≥ 50% was an independent predictive factor for pCR in patients with HER2(+) BC treated with trastuzumab-based chemotherapy.

Shallow whole genome sequencing for robust copy number profiling of formalin-fixed paraffin-embedded breast cancers.

Pathology archives with linked clinical data are an invaluable resource for translational research, with the limitation that most cancer samples are formalin-fixed paraffin-embedded (FFPE) tissues. Therefore, FFPE tissues are an important resource for genomic profiling studies but are under-utilised due to the low amount and quality of extracted nucleic acids. We profiled the copy number landscape of 356 breast cancer patients using DNA extracted FFPE tissues by shallow whole genome sequencing. We generated a total of 491 sequencing libraries from 2 kits and obtained data from 98.4% of libraries with 86.4% being of good quality. We generated libraries from as low as 3.8 ng of input DNA and found that the success was independent of input DNA amount and quality, processing site and age of the fixed tissues. Since copy number alterations (CNA) play a major role in breast cancer, it is imperative that we are able to use FFPE archives and we have shown in this study that sWGS is a robust method to do such profiling.

Abstract P3-07-14: Prosigna® intrinsic subtyping predicts response to neoadjuvant combination therapy in study that includes herceptin within HER2+ (IHC) patients

Background: The role of the HER2-enriched (HER2E) subtype determined by the Prosigna Assay in the neoadjuvant setting has remained largely uncharacterized. In this study, we examine whether Prosigna can identify a subgroup of HER2+ patients for whom combination neoadjuvant therapy that includes trastuzumab (Herceptin) is associated with a greater likelihood of pathological complete response (pCR). Methods: In this single-arm retrospective analysis, 75 patients determined to be HER2+ by IHC were treated with a neoadjuvant regimen (NAC) consisting of 8-12 cycles of anthracyclines and taxanes as well as Herceptin. The Prosigna Assay was performed on the NanoString nCounter® Dx Analysis System at HU Virgende la Victoria de Malaga/CIMES-UMA. pCR was used as the endpoint for this study and was determined using the Miller & Payne scoring criteria. Results: Mean patient age for this study population was 49 (±11.1yr) and all patients were determined to be HER2+ by IHC. The overall pCR rate in this patient population was 46.2%. Of the 75 patient samples analyzed for this study, 59 (78.6%) were HER2E, 4 (5.3%) were Luminal A and 12 (16.1%) were Luminal B, as identified by the Prosigna Assay. Of the 16 tumors classified as Luminal (A or B) by Prosigna within this HER2+ population, only 2 (12.5%) responders were observed. Categorical analysis revealed that Prosigna subtype predicted response to a NAC regimen combined with Herceptin (Odds ratio [Her2E vs. non-Her2E]=6.4, p=0.023). Further analysis of the Her2E subtype revealed that tumors with profile expression that correlated well with the prototypical Her2E centroid were significantly more likely to respond to combination NAC and Herceptin (Odds ratio [Unit increase of 1 in Her2E correlation]=88.2, p=0.004). Conclusions: The results of this study indicate that HER2+ patients with greater correlations to the HER2E subtype have an increased likelihood of response to combination neoadjuvant regimens that included HER2-targeted therapy. Citation Format: Santonja A, Ribelles N, Jimenez-Rodriguez B, Sanchez Rovira P, Alvarez M, Vicioso L, Isabel Fernandez A, de Luque V, Fernandez de Sousa C, Villar E, Zarcos I, Ramirez C, Gonzalez-Hermoso C, Jeiranian A, Dowidar N, Schaper C, Buckingham W, Ferree S, Jimenez A, Prat A, Alba E. Prosigna® intrinsic subtyping predicts response to neoadjuvant combination therapy in study that includes herceptin within HER2+ (IHC) patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-14.

Triple negative breast cancer subtypes and pathologic complete response rate to neoadjuvant chemotherapy

Triple negative breast cancer (TNBC) is a heterogeneous disease with distinct molecular subtypes that differentially respond to chemotherapy and targeted agents. The purpose of this study is to explore the clinical relevance of Lehmann TNBC subtypes by identifying any differences in response to neoadjuvant chemotherapy among them. We determined Lehmann subtypes by gene expression profiling in paraffined pre-treatment tumor biopsies from 125 TNBC patients treated with neoadjuvant anthracyclines and/or taxanes +/- carboplatin. We explored the clinicopathological characteristics of Lehmann subtypes and their association with the pathologic complete response (pCR) to different treatments. The global pCR rate was 37%, and it was unevenly distributed within Lehmann’s subtypes. Basal-like 1 (BL1) tumors exhibited the highest pCR to carboplatin containing regimens (80% vs 23%, p=0.027) and were the most proliferative (Ki-67>50% of 88.2% vs. 63.7%, p=0.02). Luminal-androgen receptor (LAR) patients achieved the lowest pCR to all treatments (14.3% vs 42.7%, p=0.045 when excluding mesenchymal stem-like (MSL) samples) and were the group with the lowest proliferation (Ki-67≤50% of 71% vs 27%, p=0.002). In our cohort, only tumors with LAR phenotype presented non-basal-like intrinsic subtypes (HER2-enriched and luminal A). TNBC patients present tumors with a high genetic diversity ranging from highly proliferative tumors, likely responsive to platinum-based therapies, to a subset of chemoresistant tumors with low proliferation and luminal characteristics.

Male breast cancer: correlation between immunohistochemical subtyping and PAM50 intrinsic subtypes, and the subsequent clinical outcomes

Male breast cancer is a rare disease that is still poorly understood. It is mainly classified by immunohistochemistry as a luminal disease. In this study, we assess for the first time the correlation between molecular subtypes based on a validated six-marker immunohistochemical panel and PAM50 signature in male breast cancer, and the subsequent clinical outcome of these different subtypes. We collected 67 surgical specimens of invasive male breast cancer from four different Spanish pathology laboratories. Immunohistochemical staining for the six-marker panel was performed on tissue microarrays. PAM50 subtypes were determined in a research-use-only nCounter Analysis System. We explored the association of immunohistochemical and PAM50 subtypes. Overall survival and disease-free survival were analyzed in the different subtypes of each classification. The distribution of tumor molecular subtypes according PAM50 was: 60% luminal B, 30% luminal A and 10% human epidermal growth factor receptor 2 (Her2) enriched. Only one Her2-enriched tumor was also positive by immunohistochemistry and was treated with trastuzumab. None of the tumors were basal-like. Using immunohistochemical surrogates, 51% of the tumors were luminal B, 44% luminal A, 4% triple-negative and 1% Her2-positive. The clinicopathological characteristics did not differ significantly between immunohistochemical and PAM50 subtypes. We found a significant worse overall survival in Her2-enriched compared with luminal tumors. Male breast cancer seems to be mainly a genomic luminal disease with a predominance of the luminal B subtype. In addition, we found a proportion of patients with Her2-negative by immunohistochemistry but Her2-enriched profile by PAM50 tumors with a worse outcome compared with luminal subtypes that may benefit from anti-Her2 therapies.