Wook Youn Kim

MicroRNA-146a Downregulates NFκB Activity via Targeting TRAF6 and Functions as a Tumor Suppressor Having Strong Prognostic Implications in NK/T Cell Lymphoma

Purpose: We investigated prognostic implications of microRNAs in extranodal NK/T cell lymphoma (NKTL). Experimental Design: We measured miRNA expression in NKTL tissues and cell lines, using real-time PCR, and analyzed its role in NKTL, using cell lines. Results: Multivariate analysis showed low miR-146a expression (P < 0.001; HR = 13.110), primary non–upper aerodigestive tract lesion (non-UAT; P = 0.008; HR = 5.376) and high International Prognostic Index (IPI; ≥3; P = 0.013; HR = 3.584) to be independent poor prognostic factors. miR-146a expression could subdivide UAT-NKTL into 2 prognostic groups, resulting in the following prognostic groups: (i) UATLow-146a, (ii) UATHigh-146a, and (iii) non-UAT. Compared with UATHigh-146a, UATLow-146a showed distinctively poor prognosis (P < 0.001; HR = 15.620), similar to the non-UAT group. In vitro, miR-146a overexpression in NKTL cell lines, SNK6 and YT, inhibited nuclear factor κB (NFκB) activity, suppressed cell proliferation, induced apoptosis, and enhanced chemosensitivity. TNF receptor–associated factor 6, a target of miR-146a and a known NFκB activator, was downregulated by miR-146a in SNK6 and YT cells. Promoter methylation of miR-146a gene was observed in SNK6 and YT cells, as well as in NKTL tissues with low miR-146a expression, and miR-146a expression was induced by the conversion of methylation status with a demethylating agent in SNK6 and YT cells. Conclusions: These results suggest that miR-146a might function as a potent tumor suppressor in NKTL and be useful for patient assessment and therapeutic targeting. Clin Cancer Res; 17(14); 4761–71. ©2011 AACR.

Follicular dendritic cell sarcoma with immature T-cell proliferation

Follicular dendritic cell sarcoma is characterized by proliferation of spindled to ovoid cells reminiscent of follicular dendritic cells. However, the association of follicular dendritic cell sarcoma with a dense infiltration of immature T cells has not hitherto been reported. We report an unusual case of follicular dendritic cell sarcoma of the mesentery with immature T-cell proliferation in a 68-year-old man. The infiltrating immature T cells demonstrated expression of CD3, CD1a, TdT, and coexpression of CD4 and CD8 by immunohistochemistry. In addition, the patient was subsequently diagnosed with myasthenia gravis and paraneoplastic pemphigus and died of distant metastasis within 2 years after initial diagnosis of follicular dendritic cell sarcoma. The aggressive clinical course of this case contrasts with the indolent course of follicular dendritic cell sarcomas, and thus, the prognostic implications of follicular dendritic cell sarcoma with immature T-cell proliferation require clarification. The complication of myasthenia gravis and paraneoplastic pemphigus may suggest that immature T-cell proliferation has an autoimmunity-related systemic influence.

Prognostic implications of CD30 expression in extranodal natural killer/T-cell lymphoma according to treatment modalities

Abstract Extranodal natural killer/T-cell lymphoma (NKTCL) has aggressive behaviors and poor clinical outcomes. A monomethyl auristatin E-conjugated anti-CD30 antibody (brentuximab vedotin) was recently introduced to treat CD30-positive lymphomas. Thus we investigated the clinicopathological features and prognostic implications of CD30 expression in 72 patients with NKTCL. CD30-positive cases, defined as cases with CD30 expression in more than 1%, 5% and 25% of tumor cells as cut-off values (COVs), accounted for 40 (56%), 27 (38%) and 16 (22%) cases of NKTCL, respectively. CD30 expression was significantly higher in large/anaplastic cell-predominant NKTCL than in small/medium cell-predominant cases. CD30-positive NKTCL showed better responses to non-anthracycline-based therapy. CD30-positive NKTCL with COV of 25% showed a lower rate of relapse. Moreover, in patients treated with non-anthracycline-based chemotherapy, CD30 positivity with COV of 5% was significantly and independently associated with longer overall survival. CD30 may be useful as a prognostic factor and therapeutic target in NKTCL.

Preoperative RAS Mutational Analysis Is of Great Value in Predicting Follicular Variant of Papillary Thyroid Carcinoma

Follicular variant of papillary thyroid carcinoma (FVPTC), particularly the encapsulated subtype, often causes a diagnostic dilemma. We reconfirmed the molecular profiles in a large number of FVPTCs and investigated the efficacy of the preoperative mutational analysis in indeterminate thyroid nodules. BRAF V600E/K601E and RAS mutational analysis was performed on 187 FVPTCs. Of these, 132 (70.6%) had a point mutation in one of the BRAF V600E (n = 57), BRAF K601E (n = 11), or RAS (n = 64) genes. All mutations were mutually exclusive. The most common RAS mutations were at NRAS codon 61. FNA aspirates from 564 indeterminate nodules were prospectively tested for BRAF and RAS mutation and the surgical outcome was correlated with the mutational status. Fifty-seven and 47 cases were positive for BRAF and RAS mutation, respectively. Twenty-seven RAS-positive patients underwent surgery and all except one patient had FVPTC. The PPV and accuracy of RAS mutational analysis for predicting FVPTC were 96% and 84%, respectively. BRAF or RAS mutations were present in more than two-thirds of FVPTCs and these were mutually exclusive. BRAF mutational analysis followed by N, H, and KRAS codon 61 mutational analysis in indeterminate thyroid nodules would streamline the management of patients with malignancies, mostly FVPTC.

Syntenin increases the invasiveness of small cell lung cancer cells by activating p38, AKT, focal adhesion kinase and SP1

Syntenin is a PDZ domain-containing adaptor protein that has been recently shown to regulate migration and invasion in several tumors. Small cell lung cancer (SCLC) is notorious for its invasiveness and strong potential for metastasis. We therefore studied the influence of syntenin on the invasiveness of SCLC. Immunohistochemistry in tumor tissues showed that syntenin was more frequently expressed in small cell carcinomas than other neuroendocrine tumors, such as carcinoids and neuroblastomas, suggesting that syntenin expression may be related to more aggressive forms of neuroendocrine tumors. In SCLC patients, syntenin overexpression in tumor cells was significantly associated with more extensive and advanced disease at the time of diagnosis (P=0.029). Overexpression of syntenin in SCLC cells that were intrinsically syntenin-low increased the invasiveness of cells and led to the induction of extracellular matrix (ECM)-degrading membrane type 1-matrix metalloproteinase (MT1-MMP) and matrix metalloproteinase 2 (MMP2). In contrast, suppression of syntenin in syntenin-high cells was associated with the downregulation of MT1-MMP. Contrary to the results of previous studies using malignant melanomas and breast carcinomas, signaling cascades were shown to be further transduced through p38 MAPK and PI3K/AKT, with activation of SP1 rather than NF-κB, under circumstances not involving ECM interaction. In addition, the upstream molecule focal adhesion kinase was induced by syntenin activation, in spite of the absence of ECM interaction. These results suggest that syntenin might contribute to the invasiveness of SCLC and could be utilized as a new therapeutic target for controlling invasion and metastasis in SCLC.

Class III β-Tubulin Shows Unique Expression Patterns in a Variety of Neoplastic and Non-neoplastic Lymphoproliferative Disorders:

Class III β-tubulin (TUBB3) expression in carcinoma is associated with resistance to tubulin-binding chemotherapeutic agents. Recently, follicular dendritic cells (FDCs) were reported to express TUBB3 under physiologic conditions. We investigated TUBB3 expression in a wide range of lymphoproliferative disorders using immunohistochemistry. Dual immunostaining for Bcl-6 and TUBB3 revealed that some germinal center B cells also express TUBB3 in addition to FDCs. In Hodgkin lymphomas (HLs), 47.1% (40/85) expressed TUBB3 in the tumor cells with an all-or-none pattern. TUBB3 expression in HL was more common in mixed cellularity type than nodular sclerosis type (P=0.032). Among non-HLs, 79.3% (23/29) of anaplastic large cell lymphoma (ALCL), 8% (2/25) of extranodal natural killer/T-cell lymphoma, and 75% (21/28) of Burkitt lymphoma showed TUBB3 expression with an all-or-none pattern. Of diffuse large B-cell lymphoma, 15.2% (32/210) expressed TUBB3 in a heterogeneous pattern. In ALCL, TUBB3 expression was more common in systemic ALCL than in primary cutaneous ALCL (P=0.046). Diffuse large B-cell lymphomas with a germinal center B-like subgroup exhibited TUBB3 expression more frequently than non−GCB-like subgroup (P=0.01). Otherwise, none of the 18 angioimmunoblastic T-cell lymphomas; 18 peripheral T-cell lymphomas, not otherwise specified; 12 follicular lymphomas; 62 marginal zone lymphomas; 7 mantle cell lymphomas; 8 small lymphocytic lymphomas; or 2 FDC sarcomas expressed TUBB3. In angioimmunoblastic T-cell lymphoma and Castleman disease, TUBB3 was positive in immunoblasts corresponding to Epstein-Barr virus-infected or Kaposi sarcoma herpes virus-infected cells. A variety of neoplastic and non-neoplastic lymphoproliferative disorders exhibited characteristic TUBB3 expression patterns; these results suggest potential for diagnostic utility, some insight into the pathobiology of TUBB3 expression, and potential therapeutic implications.

Rhabdoid colorectal carcinomas: reports of two cases.

Rhabdoid colorectal carcinomas are very rare and only 10 cases have been previously reported. We report two cases of rhabdoid colorectal carcinoma, one arising in the sigmoid colon of a 62-year-old man and another in the rectum of an 83-year-old woman. In both cases, the patients had advanced tumors with lymph node metastases. The tumors mostly showed a diffuse arrangement with rhabdoid features and small glandular regions were combined. Transitional areas from the adenocarcinomas to the rhabdoid tumors were also noted. Adenocarcinoma cells were positive for mixed cytokeratin (CK), CK20 and epithelial membranous antigen (EMA), but focal positive for vimentin. The rhabdoid tumor cells were positive for mixed CK, but focal positive or negative for CK20 and EMA. In addition, they were diffusely positive for vimentin, but negative for desmin. The histological and immunohistologial findings of these two cases suggest that the rhabodid tumor cells originated from dedifferentiated adenocarcinomas.

Development of an Ammonium Sulfate DNA Extraction Method for Obtaining Amplifiable DNA in a Small Number of Cells and Its Application to Clinical Specimens

DNA extraction from microdissected cells has become essential for handling clinical specimens with advances in molecular pathology. Conventional methods have limitations for extracting amplifiable DNA from specimens containing a small number of cells. We developed an ammonium sulfate DNA extraction method (A) and compared it with two other methods (B and C). DNA quality and quantity, β-globin amplification, and detectability of two cancer associated gene mutations were evaluated. Method A showed the best DNA yield, particularly when the cell number was very low. Amplification of the β-globin gene using DNA from the SNU 790 cell line and papillary thyroid carcinoma (PTC) cells extracted with Method A demonstrated the strongest band. BRAF V600E mutation analysis using ethanol-fixed PTC cells from a patient demonstrated both a “T” peak increase and an adjacent “A” peak decrease when 25 and 50 cells were extracted, whereas mutant peaks were too low to be analyzed using the other two methods. EGFR mutation analysis using formalin-fixed paraffin-embedded lung cancer tissues demonstrated a mutant peak with Method A, whereas the mutant peak was undetectable with Methods B or C. Method A yielded the best DNA quantity and quality with outstanding efficiency, particularly when paucicellular specimens were used.

Clinical significance of tumor-infiltrating FOXP3+ T cells in patients with ocular adnexal mucosa-associated lymphoid tissue lymphoma.

We evaluated the association between tumor‐infiltrating FOXP3+ T cells and clinical outcomes in patients with ocular adnexal lymphoma of mucosa‐associated lymphoid tissue type (OAML). Pretreatment formalin‐fixed paraffin‐embedded tissues from 42 patients with OAML were stained with 236A/E7 anti‐FOXP3 murine monoclonal antibody as well as CD3, CD4 and CD8 antibodies. The amount of FOXP3+ T cells was numerically quantified using an image analysis program. Front‐line treatments were as follows: combination chemotherapy (n = 25); radiotherapy (n = 9); doxycycline (n = 6); and wait and see (n = 2). Complete response (CR) was observed in 20 (50%) of 40 evaluable patients. Median progression‐free survival (PFS) was 50 months. A high number of FOXP3+ T cells (n = 21, ≥180/0.58 mm2) showed a higher CR rate (33%vs 71%, P = 0.013) and tendency towards prolonged PFS (48 vs 67 months, P = 0.110). In the combination chemotherapy group, a high number of FOXP3+ T cells was significantly associated with a higher CR rate (29%vs 82%, P = 0.008) and prolonged PFS (17 vs 79 months, P = 0.003). A high number of tumor‐infiltrating FOXP3+ T cells correlates with a favorable clinical outcome in OAML patients. (Cancer Sci 2011; 102: 1972–1976)

A Case of Multifocal Papillary Thyroid Carcinoma Consisting of One Encapsulated Follicular Variant with BRAF K601E Mutation and Three Conventional Types with BRAF V600E Mutation

Multifocal papillary thyroid carcinoma (mPTC) comprises about 20-30% of PTC. In mPTC, individual tumor foci can be identical or frequently composed of different histological types including follicular, solid, tall-cell or conventional patterns. We report a case of mPTC consisting of one encapsulated follicular variant of papillary thyroid carcinoma (FVPTC) and three conventional PTCs in a 44-year-old woman. This case genetically demonstrates unique features including the simultaneous presence of the BRAF V600E (T1799A) mutation and the BRAF K601E (A1801G) mutation in conventional PTC and FVPTC, respectively.