Ja Seung Koo

Characteristics and outcomes according to molecular subtypes of breast cancer as classified by a panel of four biomarkers using immunohistochemistry

To investigate the significance of immunohistochemical molecular subtyping, we evaluated outcomes of subtypes based on estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67. Using tissue microarrays, 1006 breast cancer patients between November 1999 and August 2005 were categorized into four subtypes: luminal A (ER+ and/or PR+, HER2-, Ki-67 < 14%), luminal B (ER+ and/or PR+, HER2-, Ki-67 ≥ 14% or ER+ and/or PR+, HER2+), HER2-enriched (ER-, PR-, HER2+), and triple-negative breast cancer (TNBC) (ER-, PR-, HER2-). Demographics, recurrence patterns, and survival were retrospectively analyzed using uni-/multivariate analyses. Luminal A, luminal B, HER2-enriched, and TNBC accounted for 53.1%, 21.7%, 9.0%, and 16.2% of cases, respectively. Luminal A presented well-differentiation and more co-expression of hormone receptors comparing to luminal B. HER2-enriched showed larger size and higher nodal metastasis. TNBC demonstrated younger age at diagnosis, larger size, undifferentiation, higher proliferation, and frequent visceral metastases. The peak of recurrence for luminal A was at 36 months postoperatively, while that for HER2-enriched and TNBC peaked at 12 months. The relapse risk of luminal B was mixed. Luminal A showed the best survival, but no difference was observed between the other three subtypes. When matched by nodal status, however, TNBC showed the worst outcomes in node-positive patients. In multivariate analyses, luminal A remained a positive prognostic significance. Immunohistochemically-defined subtypes showed different features, recurrence patterns, and survival. Therefore, molecular subtypes using four biomarkers could provide clinically useful information of tumor biology and clinical behaviors, and could be used for determining treatment and surveillance strategies.

Methylation-dependent loss of RIP3 expression in cancer represses programmed necrosis in response to chemotherapeutics.

Receptor-interacting protein kinase-3 (RIP3 or RIPK3) is an essential part of the cellular machinery that executes “programmed” or “regulated” necrosis. Here we show that programmed necrosis is activated in response to many chemotherapeutic agents and contributes to chemotherapy-induced cell death. However, we show that RIP3 expression is often silenced in cancer cells due to genomic methylation near its transcriptional start site, thus RIP3-dependent activation of MLKL and downstream programmed necrosis during chemotherapeutic death is largely repressed. Nevertheless, treatment with hypomethylating agents restores RIP3 expression, and thereby promotes sensitivity to chemotherapeutics in a RIP3-dependent manner. RIP3 expression is reduced in tumors compared to normal tissue in 85% of breast cancer patients, suggesting that RIP3 deficiency is positively selected during tumor growth/development. Since hypomethylating agents are reasonably well-tolerated in patients, we propose that RIP3-deficient cancer patients may benefit from receiving hypomethylating agents to induce RIP3 expression prior to treatment with conventional chemotherapeutics.

Diffuse sclerosing variant is a major subtype of papillary thyroid carcinoma in the young.

BACKGROUND Pediatric thyroid cancer differs from adult thyroid cancer in presentation and outcome. Pediatric thyroid cancer has a higher recurrence rate and greater percentage of lymph node and pulmonary metastasis. The clinicopathologic characteristics of pediatric thyroid cancer according to the histologic subtype have not been reported, however. In this study, we determined the histological subtypes of pediatric thyroid cancer and analyzed other clinicopathologic characteristics. METHODS All patients with thyroid cancer who were admitted to Severance Hospital, Seoul, South Korea, were retrospectively reviewed; their age was <20 years at diagnosis, and they were seen between January 1995 and August 2008. RESULTS Sixty-eight patients were identified. The histologic types of thyroid carcinoma were papillary thyroid carcinoma (PTC) in 57 (83.8%), follicular carcinoma in 8 (11.8%), and poorly differentiated carcinoma in 3 (4.4%). There were 28 (41.2%) cases of diffuse sclerosing variant of papillary carcinoma (DSVPC), 26 (38.2%) of conventional PTC, 2 (2.9%) of follicular PTC, and 1 (1.5%) cribriform-morular PTC. In patients with PTC, there was a higher incidence of bilateral thyroid involvement (p = 0.003), extrathyroidal extension (p = 0.009), and lymph node involvement (p = 0.018), and lower recurrence-free survival (p = 0.032) in DSVPC than in non-DSVPC. Univariate regression analysis revealed that extrathyroidal extension (p = 0.025) and tumor size (p = 0.001) were positively associated with a shorter time to recurrence. CONCLUSION DSVPC is a major subtype of PTC in the young.

Expression of autophagy-related markers beclin-1, light chain 3A, light chain 3B and p62 according to the molecular subtype of breast cancer

Aims:   To investigate the relationship between the expression of autophagy‐related proteins, including beclin‐1, light chain (LC) 3A, LC3B, and p62, and prognosis in invasive breast cancer.

The impact of caveolin protein expression in tumor stroma on prognosis of breast cancer

We aimed to investigate the expression of caveolin-1, -2, -3, and platelet-derived growth factor (PDGF) β receptor in breast cancer cells and stroma by immunohistochemistry and to analyze their implications. The expression rates of stromal caveolin-2 and PDGF β receptor increased as the tumor progressed from ductal carcinoma in situ to microinvasive ductal carcinoma, intraductal component of invasive ductal carcinoma (IDC), and IDC (p < 0.001). The expression loss of caveolin-1 in tumor stroma of IDC correlated with high tumor stage (p < 0.001), high nodal stage (p = 0.011), high cancer stage (p = 0.005), estrogen receptor negativity (p = 0.003), and tumor recurrence (p = 0.003). In addition, the expression loss of caveolin-1 in tumor stroma was correlated with a shorter disease-free survival and an overall survival (p < 0.001). In conclusion, the loss of stromal caveolin-1 is related to poor prognosis in IDC.

Metabolic interaction between cancer cells and stromal cells according to breast cancer molecular subtype

IntroductionThe aim of this study was to investigate the differential expression of markers related to metabolic, mitochondrial and autophagy status in different molecular subtypes of breast cancer.MethodsUsing tissue microarray sections generated from 740 cases of breast cancer, we performed immunohistochemical staining for Glut-1, CAIX, MCT4, ATP synthase, glutaminase, BNIP3, Beclin-1, LC3A, LC3B and p62. Based on the immunohistochemical expression of estrogen receptor (ER), progesterone (PR), HER2, and Ki-67 labeling index, the cases were classified into luminal A, luminal B, HER2 and triple-negative breast cancer (TNBC). We further classified metabolic phenotypes of tumors according to glycolytic status by assessing Glut-1 and CAIX expression as follows: Warburg type: tumor (glycolysis type), stroma (nonglycolysis type); reverse Warburg type: tumor (nonglycolysis type), stroma (glycolysis type); mixed type: tumor (glycolysis type), stroma (glycolysis type); and null type: tumor (nonglycolysis type), stroma (nonglycolysis type).ResultsExpression of Glut-1, MCT4 and LC3A was highest in TNBC and lowest in luminal A type (P < 0.001). Tumors were classified into 298 Warburg type (40.3%), 54 reverse Warburg type (7.3%), 62 mixed type (8.4%) and 326 null type (44.0%). The mixed type had a higher histologic grade, ER negativity, PR negativity and Ki-67 index, whereas the null type showed lower histologic grade, ER positivity, PR positivity and Ki-67 index (P < 0.001). TNBC constituted the major portion of Warburg and mixed types, and luminal A consisted mainly of reverse Warburg and null types (P < 0.001).ConclusionBreast cancer is heterogeneous in its metabolic status, and therefore it can be classified into various metabolic phenotypes. Specifically, the Warburg and mixed types had strong associations with TNBC, whereas reverse the Warburg and null types had associations with the luminal type, suggesting a correlation between metabolic phenotype and the biology of breast cancer.

Differential Expression of Lipid Metabolism-Related Proteins in Different Breast Cancer Subtypes

Purpose This study aimed to determine the expression and clinical significance of proteins that are involved in lipid metabolism in human breast tumors. Methods Tumors from 476 breast cancer patients were used to construct tissue microarrays. Then, immunohistochemistry (IHC) for hormone-sensitive lipase (HSL), Perilipin 1 (PLIN1), fatty acid binding protein 4 (FABP4), carnitine palmitoyltransferase IA (CPT-1A), acyl-CoA oxidase 1 (ACOX-1), and fatty acid synthase (FASN) was performed on these microarrays. Results Breast tumors were classified into 4 subtypes: luminal A (n = 242; 50.8%), luminal B (n = 134; 28.2%), human epidermal growth factor receptor 2 (HER2) (n = 50; 10.5%), and triple negative breast cancer (TNBC) (n = 50; 10.5%). The expression of PLIN1 (p < 0.001), FABP4 (p = 0.029), CPT-1A (p = 0.001), ACOX-1 (p < 0.001), and FASN (p < 0.001) differed significantly among these tumor subtypes. Notably, PLIN1, CPT-1A, and FASN expression was highest in HER2 tumors and lowest in TNBC tumors. Similarly, the expression of FABP4 and ACOX-1 was highest in HER2 tumors and lowest in luminal A tumors. In addition, ACOX-1 positivity was associated with significantly shorter overall survival (p = 0.018). When tumor subtype was considered, FABP4 positivity was associated with significantly shorter disease-free survival (p = 0.005) and overall survival (p = 0.041) in TNBC. Conclusion Lipid metabolism-related proteins are differentially expressed in different IHC subtypes of breast cancer and some are associated with decreased survival rates.

Metabolism-related proteins are differentially expressed according to the molecular subtype of invasive breast cancer defined by surrogate immunohistochemistry.

Objective: The purpose of this study was to investigate the expression of metabolism-related proteins such as Glut-1 and carbonic anhydrase IX (CAIX) according to breast cancer molecular subtype. Methods: We generated a tissue microarray of 276 breast cancer patients and performed immunohistochemical staining for known metabolism-related proteins, which were evaluated according to the molecular subtype. Results: The expression of IGF-1, MIF, and HIF-1α was correlated with the HER-2 type (p < 0.05). Glut-1 overexpression and CAIX expression were associated with TNBC type, especially with basal-like type, high histologic grade, estrogen receptor negativity, and progesterone receptor negativity (p < 0.05). The expression of Glut-1 and CAIX was correlated with statistical significance (p < 0.001). Conclusion: We identified different patterns of expression of metabolism-related proteins according to the molecular subtypes of breast cancer defined by surrogate immunohistochemistry. Increased expression of HIF-1α, IGF-1, and MIF was noted in HER-2 type breast cancer and increased expression of Glut-1 and CAIX was noted in TNBC type breast cancer, especially in the basal-like subtype, which exhibited a glycolytic and acid-resistant tumor phenotype.

Molecular Subtypes and Tumor Response to Neoadjuvant Chemotherapy in Patients with Locally Advanced Breast Cancer

Objective: Pathologic complete response (pCR) is the most predictive factor for patients with neoadjuvant chemotherapy and we investigated the rate of pCR according to molecular subtypes defined by immunohistochemical staining. Methods: Our subjects comprised 257 breast cancer patients who received 3 cycles of anthracycline/taxane-based neoadjuvant chemotherapy. The patients were classified into 4 subtypes: luminal A, luminal B, HER2 and triple negative. We analyzed the pCR rate and treatment outcome according to these subtypes. Results: Of a total of 257 patients, the pCR rate of luminal A, luminal B, HER2 and triple negative was 3.9, 5.0, 10.5 and 21.1%, respectively (p = 0.001). The 5-year disease-free survival of the pCR group (88.4%) was higher than that of the non-pCR group (65.6%), but it was not significant (p = 0.228). Among patients who have residual disease, the 5-year disease-free survival of luminal A, luminal B, HER2 and triple negative was 64.0, 65.7, 75.2 and 66.5%, respectively (p = 0.243). Triple negative and HER2 subtypes are more sensitive to neoadjuvant chemotherapy. Conclusion: To increase the pCR rate, type-specific approaches according to subtypes, such as an addition of trastuzumab, increasing the number of cycles or a novel regimen, should be considered.

The Predictive Role of E-cadherin and Androgen Receptor on In Vitro Chemosensitivity in Triple-negative Breast Cancer

OBJECTIVE The purpose of this study was to evaluate the impact of various pathologic and biologic factors in triple-negative breast cancer (TNBC) on chemotherapy response using in vitro ATP-based chemotherapy response assay (ATP-CRA). METHODS Forty-seven cases of TNBC were included. Immunohistochemical stains for androgen receptor (AR), p53, CD10, c-kit, CK5/6, vimentin, bcl-2, E-cadherin, Ki-67 and epidermal growth factor receptor were performed. In vitro ATP-CRA was used to analyze chemosensitivity for 5-fluorouracil (5-FU), docetaxel, doxorubicin, epirubicin, vinorelbine, gemcitabine, methotrexate (MTX), oxaliplatin and paclitaxel. RESULTS The results showed that all cytotoxic agents demonstrated the trend that E-cadherin-expressing cases had a higher cell death rate than E-cadherin-negative cases. Particularly, vinorelbine showed statistical significance (P = 0.004). Cases with AR expression showed higher cell death rates than those without in 5-FU and MTX (P = 0.012 and 0.014, respectively). CONCLUSIONS E-cadherin and AR could be candidate predictive factors for chemotherapy response in TNBC. Further in vivo study is required to clarify their roles.