ADAM12 is A Potential Therapeutic Target Regulated by Hypomethylation in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype and currently lacks any effective targeted therapy. Since epigenetic alterations are a common event in TNBC, DNA methylation profiling can be useful for identifying potential biomarkers and therapeutic targets. Here, genome-wide DNA methylation from eight TNBC and six non-neoplastic tissues was analysed using Illumina Human Methylation 450K BeadChip. Results were validated by pyrosequencing in an independent cohort of 50 TNBC and 24 non-neoplastic samples, where protein expression was also assessed by immunohistochemistry. The functional role of disintegrin and metalloproteinase domain-containing protein 12(ADAM12) in TNBC cell proliferation, migration and drug response was analysed by gene expression silencing with short hairpin RNA. Three genes (Von Willenbrand factor C and Epidermal Growth Factor domain-containing protein (VWCE), tetraspanin-9 (TSPAN9) and ADAM12) were found to be exclusively hypomethylated in TNBC. Furthermore, ADAM12 hypomethylation was associated with a worse outcome in TNBC tissues and was also found in adjacent-to-tumour tissue and, preliminarily, in plasma from TNBC patients. In addition, ADAM12 silencing decreased TNBC cell proliferation and migration and improved doxorubicin sensitivity in TNBC cells. Our results indicate that ADAM12 is a potential therapeutic target and its hypomethylation could be a poor outcome biomarker in TNBC.

Reproducibility and predictive value of scoring stromal tumour infiltrating lymphocytes in triple-negative breast cancer: a multi-institutional study.

BACKGROUND: Several studies have demonstrated a prognostic role for stromal tumour infiltrating lymphocytes (sTILs) in triple-negative breast cancer (TNBC). The reproducibility of scoring sTILs is variable with potentially excellent concordance being achievable using a software tool. We examined agreement between breast pathologists across Europe scoring sTILs on H&E-stained sections without software, an approach that is easily applied in clinical practice. The association between sTILs and response to anthracycline-taxane NACT was also examined. METHODOLOGY: Pathologists from the European Working Group for Breast Screening Pathology scored sTILs in 84 slides from 75 TNBCs using the immune-oncology biomarker working group guidance in two circulations. There were 16 participants in the first and 19 in the second circulation. RESULTS: Moderate agreement was achieved for absolute sTILs scores (intraclass correlation coefficient (ICC) = 0.683, 95% CI 0.601-0.767, p-value < 0.001). Agreement was less when a 25% threshold was used (ICC 0.509, 95% CI 0.416-0.614, p-value < 0.001) and for lymphocyte predominant breast cancer (LPBC) (ICC 0.504, 95% CI 0.412-0.610, p-value < 0.001). Intra-observer agreement was strong for absolute sTIL values (Spearman ρ = 0.727); fair for sTILs ≥ 25% (κ = 0.53) and for LPBC (κ = 0.49), but poor for sTILs as 10% increments (κ = 0.24). Increasing sTILs was significantly associated with an increased likelihood of a pathological complete response (pCR) on multivariable analysis. CONCLUSION: Increasing sTILs in TNBCs improves the likelihood of a pCR. However, inter-observer agreement is such that H&E-based assessment is not sufficiently reproducible for clinical application. Other methodologies should be explored, but may be at the cost of ease of application.

Cutaneous Malignant Melanoma With Rhabdoid Morphology and Smooth Muscle Differentiation: A Challenging Histopathologic Diagnosis.

Divergent differentiation or metaplastic change is a rare feature exhibited occasionally in malignant melanoma (MM), which is characterized by the development of morphologically, immunochemically, and/or ultrastructurally nonmelanocytic cells within the tumor. Smooth muscle differentiation in MM is an exceedingly rare phenomenon reported only in a few cases in the literature. We report the case of a 69-year-old woman who presented with a pure dermal amelanotic MM with smooth muscle cell differentiation and an area of rhabdoid morphology, which made the accurate histopathologic diagnostic of MM challenging.

Mixed adenoneuroendocrine carcinoma (MANEC) of the gastroesophageal junction: a case report and review of the literature.

Esophageal cancer is the fourth most common neoplasm of the gastrointestinal tract. It is responsible for 1.7% of all deaths related with cancer. The two main types of esophageal cancer are squamous cell carcinoma and adenocarcinoma. Other types of esophageal cancer are uncommon. We present a 57-year-old man admitted to the hospital with nausea and vomiting due to a high-grade malignant mixed adenoneuroendocrine carcinoma of the gastroesophageal junction. The patient underwent Ivor-Lewis esophagectomy and adyuvant chemoradiotherapy. At 8-month follow-up he was alive without evidence of recurrence.

Primary anorectal malignant melanoma: an uncommon anorectal pathology.

Anorectal malignant melanoma (AMM) is most common primary melanoma of gastrointestinal tract, accounting for 0.05% and 1% of all colorectal and anal cancers. We reported an 85 year-old woman with no significant past medical history who presented two-month period of rectal bleeding, abdominal pain, tenesmus and 2kg weight-loss. Laboratory markers were unremarkable, although rectal examination revealed two small haemorrhoids and a firm, non-obstructing mass in the lower rectum. Colonoscopy confirmed presence of an ulcerated pigmented neoplasm arising at dental line [A,B]. No distant metastases were found on computed tomography [C] although presented metastatic regional lymph nodes on pelvic MRI [D]. Therefore, abdominoperineal resection was performed, confirming loco-regional disease. Histopathology showed malignant melanoma with positive stains in immunohistochemistry for protein S100, HMB-45 and Melan-A [E,F,G,H] and stained negative for c-Kit.

Primary Cutaneous Acral CD8-Positive Lymphoproliferative Disorder: A Case Report With Nonacral Presentation.

In this study, we describe a patient of primary cutaneous acral CD8-positive lymphoproliferative disorder located in a nonacral region. A 65-year-old male presented with an ill-defined lesion of rubbery consistency and a maximum diameter of 2.5 cm localized in the right thigh. Histologically, it was composed of a diffuse dermal infiltration of medium-sized atypical lymphocytes that expressed CD3, CD8, and TIA-1. In addition, a characteristic paranuclear positivity with CD68 was observed. During the follow-up, the patient had a recurrence of the disease in the abdomen with a lesion showing similar morphology and phenotype. To our knowledge, < 20 patients of primary cutaneous acral CD8-positive lymphoproliferative disorder with a nonacral presentation have been described in English literature. Although rare, its identification is essential to differentiate it from other T-cell lymphoma that express CD8 and cytotoxic markers, and whose clinical courses are very aggressive.

Cardiac Metastasis From Solid Cancers: A 35-Year Single-Center Autopsy Study.

CONTEXT.­: Cardiac metastases are more prevalent than primary cardiac tumors, and although rare, the incidence is anticipated to increase with the extended survival of oncology patients. OBJECTIVE.­: To estimate the current incidence of cardiac metastasis from solid tumors in adult autopsies. DESIGN.­: Adult autopsy cases from 1984 through 2019 from patients diagnosed with any type of solid cancer were retrieved. The medical charts and pathologic autopsy data were reviewed in detail. RESULTS.­: A total of 1294 adult autopsies performed on patients diagnosed with any type of cancer within the past 35 years were reviewed. We found 124 secondary cardiac tumors. Eighty-five were due to cardiac involvement by solid tumors. Of these, 61 were true cardiac metastases of solid cancers. We focused on these 61 cases. The age range was 32 to 85 years. Forty-four patients were men and 17 were women. The lung was the most common primary site, with 21 cases (34.43%). The most frequent histologic type was carcinoma, with 54 cases (88.52%). The predominant layer of the heart involved was the pericardium, with 35 cases (57.38%). Twenty-one cases (34.43%) had pericardial effusion, with 4 being hemorrhagic. All cases had multiple extracardiac metastases, with 56 cases (91.8%) having distant metastases in 4 or more different organs. CONCLUSIONS.­: Cardiac metastasis is a rare occurrence, with an incidence of 4.71% (61 of 1294 cases) in our series. Lung cancer accounted for most of the cardiac metastases seen, and carcinomas were the most frequent histologic type. The pericardium was the most frequent location. Cardiac metastases occurred most frequently in cases of massive metastatic dissemination.

Pleomorphic carcinoma of the breast with expression of macrophage markers: report of two cases.

Pleomorphic ductal carcinoma of the breast is a rare variant included in the morphological group of infiltrating ductal carcinoma. The pleomorphic carcinoma is composed predominantly of epithelial and multinucleated tumor giant cells. We report here two cases presenting a lesion composed microscopically of a proliferation of large pleomorphic cells with a predominance of multinucleated giant cells. These lesions were negative for estrogen receptor, progesterone receptor and Her2-neu (triple-negative phenotype). Basal markers (cytokeratin 5/6, cytokeratin 17 and epidermal growth factor receptor [EGFR]) were present, accompanied by the presence of histiocyte marker CD163 in most neoplastic giant cells. High-grade pleomorphic breast carcinomas with the triple-negative phenotype and expression of basal markers might be included in the basal subtype. This is the first report about the co-expression of macrophage marker CD163, with tumor (P53) or epithelial markers (CAM5.2), as indicated by double immunohistochemistry in pleomorphic ductal carcinoma of the breast.

Clinical and pathological features of Merkel cell carcinoma: A 4-year follow-up observational retrospective study in Spain.

BACKGROUND: Merkel cell carcinoma (MCC) is a malignant skin cancer with a 5-year survival rate of approximately 50%. Knowledge of MCC has increased in recent years mostly due to improved diagnosis techniques. In Spain there is lack of information regarding the incidence and tumour characteristics, and the treatment approaches are not standardised. The objective of this study was to provide information of the clinical and epidemiological characteristics of MCC patients in Spain. METHODS: Retrospective, observational study involving 192 patients from 25 Spanish hospitals. Evaluated variables included overall survival and incidence rate of Merkel cell polyomavirus, in patients diagnosed from 2012 to 2016. RESULTS: The Spanish incidence rate was estimated 0.32/100,000 inhabitants/year, with variations according to geographical regions, being slightly higher in areas with greater sunlight exposure. In total, 61.5% of tumours showed expansive growth (progressive growth of the tumour), 78.6% showed localisation in UV-exposed skin. 97.4% of patients were diagnosed by excisional biopsy. Surgery was the first line treatment in 96.6% of patients, radiotherapy in 24.6%, and chemotherapy in 6.3%. These treatments were not mutually exclusive. Median overall survival was 38.3 months (78.4% at 12 months and 60% at 24 months). MCPyV was present in 33.8% of patients. CONCLUSION: The incidence of MCC in Spain is one of the highest in Europe, with a slight predominance in men. The sample has shown that a biopsy is available for diagnosis in most cases. Moreover, the treatment is surgical when the tumour is localized and is associated with lymphadenectomy, and/or it is radiotherapy if widespread.

Prognostic Value of Stromal Tumor-Infiltrating Lymphocytes in Young, Node-Negative, Triple-Negative Breast Cancer Patients Who Did Not Receive (neo)Adjuvant Systemic Therapy.

PURPOSE: Triple-negative breast cancer (TNBC) is considered aggressive, and therefore, virtually all young patients with TNBC receive (neo)adjuvant chemotherapy. Increased stromal tumor-infiltrating lymphocytes (sTILs) have been associated with a favorable prognosis in TNBC. However, whether this association holds for patients who are node-negative (N0), young (< 40 years), and chemotherapy-naïve, and thus can be used for chemotherapy de-escalation strategies, is unknown. METHODS: We selected all patients with N0 TNBC diagnosed between 1989 and 2000 from a Dutch population-based registry. Patients were age < 40 years at diagnosis and had not received (neo)adjuvant systemic therapy, as was standard practice at the time. Formalin-fixed paraffin-embedded blocks were retrieved (PALGA: Dutch Pathology Registry), and a pathology review including sTILs was performed. Patients were categorized according to sTILs (< 30%, 30%-75%, and ≥ 75%). Multivariable Cox regression was performed for overall survival, with or without sTILs as a covariate. Cumulative incidence of distant metastasis or death was analyzed in a competing risk model, with second primary tumors as competing risk. RESULTS: sTILs were scored for 441 patients. High sTILs (≥ 75%; 21%) translated into an excellent prognosis with a 15-year cumulative incidence of a distant metastasis or death of only 2.1% (95% CI, 0 to 5.0), whereas low sTILs (< 30%; 52%) had an unfavorable prognosis with a 15-year cumulative incidence of a distant metastasis or death of 38.4% (32.1 to 44.6). In addition, every 10% increment of sTILs decreased the risk of death by 19% (adjusted hazard ratio: 0.81; 95% CI, 0.76 to 0.87), which are an independent predictor adding prognostic information to standard clinicopathologic variables (χ2 = 46.7, P < .001). CONCLUSION: Chemotherapy-naïve, young patients with N0 TNBC with high sTILs (≥ 75%) have an excellent long-term prognosis. Therefore, sTILs should be considered for prospective clinical trials investigating (neo)adjuvant chemotherapy de-escalation strategies.

Pre-operative management of Pleomorphic and florid lobular carcinoma in situ of the breast: Report of a large multi-institutional series and review of the literature.

BACKGROUND: Pleomorphic and Florid Lobular carcinoma in situ (P/F LCIS) are rare variants of LCIS, the exact nature of which is still debated. AIM: To collect a large series of P/F LCIS diagnosed on preoperative biopsies and evaluate their association with invasive carcinoma and high grade duct carcinoma in situ (DCIS). Data obtained were compared with those reported in the literature. METHODS: A multi-institutional series of P/F LCIS was retrieved. All cases were diagnosed on pre-operative biopsies, which was followed by an open surgical excision. Data on post-operative histopathology were available. A literature review was performed. RESULTS: A total of 117 cases were collected; invasive carcinoma and/or DCIS was present in 78/117 cases (66.7%). Seventy cases of P/F LCIS were pure on biopsy and 31 of these showed pathological upgrade in post-surgical specimens. Pre-operative biopsy accuracy was 47/78 (60.3%); pre-operative biopsy underestimation of cancer was 31/78 (39,7.%). In the literature review papers, invasive carcinoma or DCIS was associated with 274 of 418 (65.5%) cases of P/F LCIS. Pre-operative biopsy accuracy was 66% (181/274) whereas pre-operative biopsy underestimation of cancer was 33.9% (93/274). CONCLUSIONS: The data presented here indicate that P/F LCIS is frequently associated with invasive carcinoma or high grade DCIS and that pre-operative biopsy is associated with an underestimation of malignancy. Open surgery is indicated when P/F LCIS is diagnosed pre-operatively.

Differences and molecular immunohistochemical parameters in the subtypes of infiltrating ductal breast cancer.

Breast cancer is a heterogeneous disease, and patients are categorized into subtypes according to gene expression. We studied the associations among molecular, immunohistochemical, and clinicopathologic features and their distribution according to the subtypes luminal, HER2, basal, and normal-like in 60 patients with invasive ductal breast carcinoma without distant metastasis at the time of diagnosis (M0). We evaluated the hypermethylation of the CDH-1, RASSF1A, SIAH-1 and TSLC-1 genes by methylation-specific polymerase chain reaction and the expression of p53, bcl-2, cyclin D1, E-cadherin, and beta-catenin proteins in tissue microarrays by immunohistochemical analysis. Expression of bcl-2 was associated with the luminal subtype (P=.003), and CDH-1 hypermethylation was present preferentially in HER2 tumors (P=.038). The basal subtype was characterized by the expression of beta-catenin (P=.003). The hypermethylation of CDH-1 and the expression of bcl-2, cyclin D1, and beta-catenin proteins differ among breast cancer subtypes.

Reductions in maize root-tip elongation by salt and osmotic stress do not correlate with apoplastic O2*- levels.

BACKGROUND AND AIMS: Experimental evidence in the literature suggests that O(2)(*-) produced in the elongation zone of roots and leaves by plasma membrane NADPH oxidase activity is required for growth. This study explores whether growth changes along the root tip induced by hyperosmotic treatments in Zea mays are associated with the distribution of apoplastic O(2)(*-). METHODS: Stress treatments were imposed using 150 mm NaCl or 300 mM sorbitol. Root elongation rates and the spatial distribution of growth rates in the root tip were measured. Apoplastic O(2)(*-) was determined using nitro blue tetrazolium, and H(2)O(2) was determined using 2', 7'-dichlorofluorescin. KEY RESULTS: In non-stressed plants, the distribution of accelerating growth and highest O(2)(*-) levels coincided along the root tip. Salt and osmotic stress of the same intensity had similar inhibitory effects on root elongation, but O(2)(*-) levels increased in sorbitol-treated roots and decreased in NaCl-treated roots. CONCLUSIONS: The lack of association between apoplastic O(2)(*-) levels and root growth inhibition under hyper-osmotic stress leads us to hypothesize that under those conditions the role of apoplastic O(2)(*-) may be to participate in signalling processes, that convey information on the nature of the substrate that the growing root is exploring.

Is Regression after Neoadjuvant Chemotherapy for Locally Advanced Breast Cancer Different in Sentinel and Non-sentinel Nodes?

Tumor draining sentinel lymph nodes (SLNs) are the sites of selective changes as compared to non-SLNs. They show features of tumor-reactive lymphadenopathy, including increased total number of functional blood vessels, but a relative immunosuppressed status has also been described in them. We explored the hypothesis of a selective regression or non-regression in SLNs versus non-SLNs in 142 patients with 110 estrogen receptor-positive and 32 estrogen receptor-negative tumors undergoing both SLN biopsy and axillary lymph node dissection after neoadjuvant therapy by assessing the tumoral (metastatic) and regression statuses of SLNs and non-SLNs separately. Of the 89 cases with signs of nodal regression, 22 cases (25%) were in favor of a selective non-regression in SLNs, 18 cases (20%) were supportive of a selective and more pronounced regression in the SLNs and the remaining showed equal degrees of regression or non-regression in SLNs and non-SLNs. The results indicate that there is no obvious difference in the degree of regressive histological changes shown by SLNs and NSLNs. Therefore, this phenomenon may not be a major contributor to the higher false negative rate of SLN biopsy after neoadjuvant treatment.

Care patterns and changes in treatment for nonmetastatic breast cancer in 2013-2014 versus 2005: a population-based high-resolution study.

Studies on recent trends in patterns of care for breast cancer patients are scarce. This study aims to examine the patterns and trends in the treatment of women with nonmetastatic breast cancer according to major recommended treatment options. A population-based study was carried out in Navarra, Spain, including all women with a primary invasive nonmetastasized breast cancer, diagnosed in 2005 and in 2013-2014. We compared patients' characteristics and treatment patterns between periods. Factors associated with receipt of recommended treatment were examined by multivariate logistic regression. Of the 719 patients included, 90% received guideline-adherent locoregional treatment. Over the two periods, there was an increasing use of sentinel lymph node biopsy as opposed to axillary lymph node dissection as the first axillary procedure. Among women with oestrogen receptor-positive tumours, 96% received endocrine therapy. The proportion of high-risk patients who were treated with chemotherapy increased between the two periods from 65 to 74% (P=0.079) and, among patients with human epidermal growth factor receptor 2-positive tumours, the receipt of targeted treatment increased from 37 to 72% (P<0.001). The main factors associated independently with a lower probability of receiving recommended treatment were age 70 years or older for all treatment modalities and comorbidity for locoregional treatment and chemotherapy. The proportion of women with breast cancer who received treatment according to recent European guidelines in Navarra has increased from 2005 to 2013-2014, resulting in a high level of adherence to standard care. Most failures in adherence to these standards are related to older age or comorbidities.

CDH22 hypermethylation is an independent prognostic biomarker in breast cancer.

BACKGROUND: Cadherin-like protein 22 (CDH22) is a transmembrane glycoprotein involved in cell-cell adhesion and metastasis. Its role in cancer is controversial because it has been described as being upregulated in colorectal cancer, whereas it is downregulated in metastatic melanoma. However, its status in breast cancer (BC) is unknown. The purpose of our study was to determine the molecular status and clinical value of CDH22 in BC. RESULTS: We observed by immunohistochemistry that the level of CDH22 expression was lower in BC tissues than in their matched adjacent-to-tumour and non-neoplastic tissues from reduction mammoplasties. Since epigenetic alteration is one of the main causes of gene silencing, we analysed the hypermethylation of 3 CpG sites in the CDH22 promoter by pyrosequencing in a series of 142 infiltrating duct BC cases. CDH22 was found to be hypermethylated in tumoral tissues relative to non-neoplastic mammary tissues. Importantly, this epigenetic alteration was already present in adjacent-to-tumour tissues, although to a lesser extent than in tumoral samples. Furthermore, CDH22 gene regulation was dynamically modulated in vitro by epigenetic drugs. Interestingly, CDH22 hypermethylation in all 3 CpG sites simultaneously, but not expression, was significantly associated with shorter progression-free survival (p = 0.015) and overall survival (p = 0.021) in our patient series. Importantly, CDH22 hypermethylation was an independent factor that predicts poor progression-free survival regardless of age and stage (p = 0.006). CONCLUSIONS: Our results are the first evidence that CDH22 is hypermethylated in BC and that this alteration is an independent prognostic factor in BC. Thus, CDH22 hypermethylation could be a potential biomarker of poor prognosis in BC.

Role of total tumour load of sentinel lymph node on survival in early breast cancer patients.

BACKGROUND: Axillary staging (pN) is considered one of the most important prognostic factors in breast cancer patients. However, the Z0011 study data drastically reduced the number of surgical axillary dissections in a selected group of patients, limiting the prognostic information relating to axillary involvement to the sentinel lymph node (SLN). It is known that there is a relationship between SLN total tumour load (TTL) and axillary involvement. The objective of this study is to analyse the relationship between the TTL and outcomes in patients with early stage breast cancer. PATIENTS AND METHODS: clinicopathological and follow-up data were collected from 950 patients with breast cancer between 2009 and 2010 on whom SLN analysis was conducted by molecular methods (One Step Nucleic Acid Amplification, Sysmex, Kobe, Japan). RESULTS: TTL (defined as the total number of CK19 mRNA copies in all positive SLN) correlates with disease free survival (HR, 1.08; p = 0.000004), with local recurrence disease free survival (HR = 1.07; p = 0.0014) and overall survival (HR: 1.08, p = 0.0032), clearly defining a low-risk group (TTL <2.5 × 104 CK19 mRNA copies/µL) versus a high-risk group (>2.5 × 104 CK 19 mRNA copies/µL). CONCLUSIONS: SLN TTL permits the differentiation between two patient groups in terms of DFS and OS, independently of axillary staging (pN), age and tumour characteristics (size, grade, lymphovascular invasion). This new data confirms the clinical value of low axillary involvement and could partially replace the information that staging of the entire axilla provides in patients on whom no axillary lymph node dissection is performed.

CHL1 hypermethylation as a potential biomarker of poor prognosis in breast cancer.

The CHL1 gene encodes a cell-adhesion molecule proposed as being a putative tumour-suppressor gene in breast cancer (BC). However, neither the underlying molecular mechanisms nor the clinical value of CHL1 downregulation in BC has been explored. The methylation status of three CpG sites in the CHL1 promoter was analysed by pyrosequencing in neoplastic biopsies from 142 patients with invasive BC and compared with that of non-neoplastic tissues. We found higher CHL1 methylation levels in breast tumours than in non-neoplastic tissues, either from mammoplasties or adjacent-to-tumour, which correlated with lower levels of protein expression in tumours measured by immunohistochemistry. A panel of five BC cell lines was treated with two epigenetic drugs, and restoration of CHL1 expression was observed, indicating in vitro dynamic epigenetic regulation. CHL1 was silenced by shRNA in immortalized but non-neoplastic mammary cells, and enhanced cell proliferation and migration, but not invasion, were found by real-time cell analysis. The prognostic value of CHL1 hypermethylation was assessed by the log-rank test and fitted in a Cox regression model. Importantly, CHL1 hypermethylation was very significantly associated with shorter progression-free survival in our BC patient series, independent of age and stage (p = 0.001). In conclusion, our results indicate that CHL1 is downregulated by hypermethylation and that this epigenetic alteration is an independent prognostic factor in BC.

Long-term prognosis of young breast cancer patients (≤40 years) who did not receive adjuvant systemic treatment: protocol for the PARADIGM initiative cohort study.

INTRODUCTION: Currently used tools for breast cancer prognostication and prediction may not adequately reflect a young patient's prognosis or likely treatment benefit because they were not adequately validated in young patients. Since breast cancers diagnosed at a young age are considered prognostically unfavourable, many treatment guidelines recommend adjuvant systemic treatment for all young patients. Patients cured by locoregional treatment alone are, therefore, overtreated. Lack of prognosticators for young breast cancer patients represents an unmet medical need and has led to the initiation of the PAtients with bReAst cancer DIaGnosed preMenopausally (PARADIGM) initiative. Our aim is to reduce overtreatment of women diagnosed with breast cancer aged ≤40 years. METHODS AND ANALYSIS: All young, adjuvant systemic treatment naive breast cancer patients, who had no prior malignancy and were diagnosed between 1989 and 2000, were identified using the population based Netherlands Cancer Registry (n=3525). Archival tumour tissues were retrieved through linkage with the Dutch nationwide pathology registry. Tissue slides will be digitalised and placed on an online image database platform for clinicopathological revision by an international team of breast pathologists. Immunohistochemical subtype will be assessed using tissue microarrays. Tumour RNA will be isolated and subjected to next-generation sequencing. Differences in gene expression found between patients with a favourable and those with a less favourable prognosis will be used to establish a prognostic classifier, using the triple negative patients as proof of principle. ETHICS AND DISSEMINATION: Observational data from the Netherlands Cancer Registry and left over archival patient material are used. Therefore, the Dutch law on Research Involving Human Subjects Act (WMO) is not applicable. The PARADIGM study received a 'non-WMO' declaration from the Medical Ethics Committee of the Netherlands Cancer Institute - Antoni van Leeuwenhoek hospital, waiving individual patient consent. All data and material used are stored in a coded way. Study results will be presented at international (breast cancer) conferences and published in peer-reviewed, open-access journals.