Young Lyun Oh

BRAFV600E Mutation Analysis in Fine-Needle Aspiration Cytology Specimens for Evaluation of Thyroid Nodule: A Large Series in a BRAFV600E-Prevalent Population

BACKGROUND The BRAFV600E mutation is highly specific to papillary thyroid carcinoma. A test for this mutation may increase the diagnostic accuracy of fine-needle aspiration cytology (FNAC), especially in a BRAFV600E mutation-prevalent population. METHODS This prospective study enrolled 1074 patients with thyroid nodules who underwent both FNAC and BRAFV600E mutation analysis by dual-priming oligonucleotide (DPO)-based multiplex PCR in FNA specimens. RESULTS The ancillary test for BRAFV600E significantly improved the sensitivity of FNA procedure, from 67.5% with FNAC alone to 89.6% with FNAC and the DPO-based multiplex PCR analysis combined. Diagnostic accuracy increased from 90.9 to 96.6%. Nine cases of papillary thyroid carcinoma were detected only by BRAFV600E mutation analysis. Unexpectedly, the preoperative DPO-based multiplex PCR produced five false-positive results, which surgery showed to represent benign nodules. CONCLUSIONS Molecular testing for the BRAFV600E mutation in FNA thyroid nodule specimens increases diagnostic value when applied in a BRAFV600E mutation-prevalent population. However, when using this potentially powerful technique, we must consider both its strengths and its weaknesses.

Prognostic factors for Korean patients with anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC), although rare, is one of the most aggressive human cancers, and patients with ATC have extremely poor prognoses despite various therapeutic measures. We wished to determine the prognostic factors of survival and effect of treatment on survival rate in patients with ATC.

The prediction of malignant risk in the category “atypia of undetermined significance/follicular lesion of undetermined significance” of the Bethesda System for Reporting Thyroid Cytopathology using subcategorization and BRAF mutation results

The “atypia of undetermined significance/follicular lesion of undetermined significance” (AUS/FLUS) category in the Bethesda System for Reporting Thyroid Cytopathology is a heterogeneous category of cases that are not clearly benign or malignant.

BRAFV600E Mutation Analysis of Thyroid Nodules Needle Aspirates in Relation to Their Ultrasongraphic Classification: A Potential Guide for Selection of Samples for Molecular Analysis

BACKGROUND Proper candidates to improve the effectiveness of molecular testing for thyroid nodules detected on ultrasonography (US) in a clinical setting are not well known. We aimed at evaluating the effective indication and method of BRAF(V600E) mutation analysis of aspiration specimens according to the US features of thyroid nodules in a BRAF(V600E) mutation-prevalent area. METHODS A total of 244 patients with 244 thyroid nodules were prospectively classified as malignant and nonmalignant based on US. Thyroid nodules with any malignant US features including spiculated margin, the presence of microcalcifications or macrocalcifications, marked hypoechogenicity, or a taller-than-wide shape were defined as US-positives and those without these features were defined as US-negatives. All patients underwent US-guided fine-needle aspiration (FNA). The presence of the BRAF(V600E) mutation in FNA specimens was determined by allele-specific polymerase chain reaction (AS-PCR) and direct DNA sequencing. The mutation results were correlated with cytology and either surgical pathology or follow-up. RESULTS Of 244 nodules, 66 were US-positive and 178 were US-negative. The malignancy rate was 92% (61/66) for US-positives and 14% (25/178) for US-negatives. The BRAF(V600E) mutation was identified in 67% (44/66) of US-positives and in 10% (17/178) of US-negatives. The BRAF(V600E) mutation for nodules with indeterminate or nondiagnostic cytology was present in 45% (5/11) of US-positives and in 8% (2/26) of US-negatives (p = 0.0168). A false negative cytology with the mutation was found in only one case of the US-negatives. All nodules with the mutation were surgically confirmed as papillary carcinomas. Adding the genetic analysis to the FNA as compared with the FNA alone improved the sensitivity and accuracy for US-positives, whereas there was no significant improvement for US-negatives. With regard to sensitivity and accuracy, the use of the AS-PCR was better than the use of the direct DNA sequencing for US-positives as compared with US-negatives. CONCLUSION The application of BRAF(V600E) mutation analysis in FNA specimens is more effective for thyroid nodules with malignant US features as compared with nodules without malignant US features. The use of the AS-PCR is more valuable as compared with the direct DNA sequencing to refine the diagnosis in a clinical setting.

Expression of p21Waf1, p27Kip1 and cyclin D1 proteins in breast ductal carcinoma in situ: Relation with clinicopathologic characteristics and with p53 expression and estrogen receptor status

p21Waf1 (p21), p27Kip1 (p27) and cyclin D1 have recently been reported as useful prognostic markers for patients with breast carcinoma. However, studies on these cell cycle regulators in ductal carcinoma in situ (DCIS) have been extremely limited. Therefore, we studied the immunohistochemical expression of p21, p27 and cyclin D1 proteins in 49 DCIS cases and compared the findings with the clinicopathologic parameters (age, tumor size, gross type, histologic type, histologic grade, necrosis and mitotic index), p53 and estrogen receptor (ER) status. A significant correlation was found between positive p21 immunoreactivity (67.3% of the cases) and well‐differentiated histologic grade, non‐comedo type, ER‐positive and p53‐negative (p53–) status. DCIS with p21+/p53– is likely to be the non‐comedo type. The overexpression of cyclin D1 (59.2% of the cases) correlated positively with the ER expression (P = 0.001). The p27 protein expression (46.9% of the cases) correlated with the cyclin D1 immunopositivity (P = 0.0003) and ER expression (P = 0.005). No significant associations were seen in the p27 or cyclin D1 expression and other clinicopathologic parameters. Our results suggest that p21 might be more related to the useful biologic markers in DCIS than p27 or cyclin D1. The significant positive association between p21, p27 or cyclin D1 and ER status, and close association of p27 and cyclin D1 expression might be implicated in the tumor biology of DCIS.

Genome-wide array-based comparative genomic hybridization of ocular marginal zone B cell lymphoma: comparison with pulmonary and nodal marginal zone B cell lymphoma.

The genetic changes in marginal zone B cell lymphomas (MZBCL) vary according to the anatomical region. This study aimed to investigate genomic aberrations in ocular MZBCL and to compare them with those of tumors from other anatomical sites. The study population comprised 24 cases of primary ocular MZBCL, 11 pulmonary MZBCL, and seven nodal MZBCL. For array CGH, fresh tumor tissues were analyzed with a genome‐wide scanning array containing 2,304 BAC/PAC clones which cover the whole human genome at a resolution of 1.3 Mb. FISH analysis for MALT1 gene alteration was performed for ocular and nodal MZBCL and RT‐PCR for the detection of API2‐MALT1 transcripts was performed for pulmonary MZBCL. The recurrent genomic alterations in ocular MZBCL were losses of chromosome bands 6q23.3 (9/24, 38%), 7q36.3 (2/24, 8%), and 13q34 (2/24, 8%), and gains of chromosomes 3 (9/24, 38%), and 15 (4/24, 16%), and chromosome arms 18q (4/24, 16%), and 6p (2/24, 8%). The t(11;18)(q21;q21) was not detected. The genomic alterations of pulmonary MZBCL included recurrent loss of 18q21 (2/11, 19%). A t(11;18)(q21;q21) fusion transcript was detected in five out of eight cases (63%). Nodal MZBCL showed neither recurrent genome alterations nor any change in MALT1 gene copy number. In conclusion, the array CGH profile of ocular MZBCL is distinct from those of pulmonary and nodal MZBCL. Deletion of chromosome band 6q23.3 in ocular MZBCL is a novel finding and may constitute a crucial genetic alteration in the pathogenesis of ocular MZBCL.

Identification of Driving ALK Fusion Genes and Genomic Landscape of Medullary Thyroid Cancer

The genetic landscape of medullary thyroid cancer (MTC) is not yet fully understood, although some oncogenic mutations have been identified. To explore genetic profiles of MTCs, formalin-fixed, paraffin-embedded tumor tissues from MTC patients were assayed on the Ion AmpliSeq Cancer Panel v2. Eighty-four sporadic MTC samples and 36 paired normal thyroid tissues were successfully sequenced. We discovered 101 hotspot mutations in 18 genes in the 84 MTC tissue samples. The most common mutation was in the ret proto-oncogene, which occurred in 47 cases followed by mutations in genes encoding Harvey rat sarcoma viral oncogene homolog (N = 14), serine/threonine kinase 11 (N = 11), v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (N = 6), mutL homolog 1 (N = 4), Kiesten rat sarcoma viral oncogene homolog (N = 3) and MET proto-oncogene (N = 3). We also evaluated anaplastic lymphoma kinase (ALK) rearrangement by immunohistochemistry and break-apart fluorescence in situ hybridization (FISH). Two of 98 screened cases were positive for ALK FISH. To identify the genomic breakpoint and 5’ fusion partner of ALK, customized targeted cancer panel sequencing was performed using DNA from tumor samples of the two patients. Glutamine:fructose-6-phosphate transaminase 1 (GFPT1)-ALK and echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusions were identified. Additional PCR analysis, followed by Sanger sequencing, confirmed the GFPT1-ALK fusion, indicating that the fusion is a result of intra-chromosomal translocation or deletion. Notably, a metastatic MTC case harboring the EML4-ALK fusion showed a dramatic response to an ALK inhibitor, crizotinib. In conclusion, we found several genetic mutations in MTC and are the first to identify ALK fusions in MTC. Our results suggest that the EML4-ALK fusion in MTC may be a potential driver mutation and a valid target of ALK inhibitors. Furthermore, the GFPT1-ALK fusion may be a potential candidate for molecular target therapy.

Micropapillary variant of transitional cell carcinoma of the ureter

Micropapillary variant of transitional cell carcinoma (TCC) is a rare entity, having a distinct micropapillary component mimicking papillary serous carcinoma of the ovary and has been reported exclusively in the urinary bladder. We experienced a case of micropapillary variant of TCC in the ureter. The tumor showed a predominant proportion of micropapillary component and accompanied a TCC in situ lesion and a high‐grade TCC. A metastatic lesion in the regional lymph node also showed an entirely micropapillary pattern. Initially, our case was confused with adenocarcinoma, especially metastatic, because the micropapillary architecture resembled an abortive glandular structure and tumor cell nests were predominantly located in empty spaces mimicking vascular invasion. The patient died with peritoneal metastases 20 months after the initial diagnosis. We report the first case of a micropapillary variant of TCC occurring in the ureter.

Expression of CD34, bcl-2, and kit in inflammatory fibroid polyps of the gastrointestinal tract.

The histogenesis of inflammatory fibroid polyps (IFP) of the gastrointestinal tract, focused on the cell of origin of the stromal cells, is a controversial subject. The reported CD34 reactivity in gastric IFP has implied a histogenetic relationship with a variety of CD34-reactive tumors, including gastrointestinal stromal tumors (GIST). In addition to bcl-2, the majority of GIST has expressed Kit, suggesting an origin in interstitial cells of Cajal (ICC), which are selectively localized around nerve plexuses. Gastric (12) and colonic (two) IFP from 13 patients were studied, using antibodies against CD34, bcl-2, and Kit. IFP expanded muscularis mucosae with prominent vascular channels, inflammatory infiltrates, proliferating stromal cells, and extracellular matrix material. Eleven gastric IFP exhibited concentric stromal proliferations (CP), particularly, around vessels, glands, and muscle bundles. Their stromal cells were CD34 reactive, bcl-2 nonreactive, and Kit nonreactive and showed fibroblast-like appearances with thin, long cytoplasmic processes. In contrast, one gastric and two colonic IFP showed no CP, and their stromal cells were CD34 nonreactive, bcl-2 nonreactive, and Kit nonreactive. IFP with CP may have a different histogenesis from IFP without CP. IFP with CP may originate from a subpopulation of dendritic interstitial cells other than ICC, predominantly localized around blood vessels and muscle fibers in muscularis mucosae of the stomach.

The cytological, clinical, and pathological features of the cribriform-morular variant of papillary thyroid carcinoma and mutation analysis of CTNNB1 and BRAF genes.

BACKGROUND The cribriform-morular variant of papillary thyroid carcinoma (CMVPTC) is an unusual subtype of papillary thyroid carcinoma. The goal of this study was to determine the clinicopathological features of CMVPTC and whether the tumor can be diagnosed by fine-needle aspiration cytology. METHODS We retrospectively analyzed the clinical appearance and pathological findings in five patients with CMVPTC and sequenced exon 3 of CTNNB1 and exon 15 of BRAF in tumor tissue. RESULTS All patients were young women, 15-34 years of age at the time of the cancer diagnosis. Preoperative cytological examination showed scattered tall columnar cells, fascicular spindle cells, and cribriform and morular patterns in the fine-needle aspirates of the thyroid from the five patients. Grossly, all tumors were well-circumscribed, solid or cystic. Immunohistochemically, most tumor cells showed nuclear expression of thyroid transcription factor-1, estrogen and progesterone receptors, and p53; cytoplasmic expression of cytokeratins 7 and 19, vimentin, and bcl-2; and cytoplasmic and nuclear accumulation of beta-catenin and galectin-3. There was no expression of thyroglobulin, cytokeratin 5/6, or human mesothelial cell-1. However, among these markers, the morular cells showed only positive immunostaining for beta-catenin, galectin-3, p53, and bcl-2. A CTNNB1 mutation was identified in only one case and no BRAF mutation was found in any of the five cases. CONCLUSIONS Taken together, these data suggest that CMVPTC can be diagnosed preoperatively, based on careful cytology examination, and shows unique immunohistochemical findings.