Chang-Jin Kim

BRAF V600E Mutation Analysis in Papillary Thyroid Carcinomas by Peptide Nucleic Acid Clamp Real-time PCR

ABSTRACTBackgroundActivating somatic mutation of the BRAFV600E has been identified as the most common genetic event in papillary thyroid carcinoma (PTC) with a variable frequency (32–87xa0%) in different series by different methods. The BRAFV600E mutation is associated with various clinicopathological parameters. The mutation is an important factor for the management of the PTC patients. The objective of this study was to detect the BRAFV600E mutation in PTCs by peptide nucleic acid (PNA) clamp real-time PCR and to analyze the results with clinicopathological parameters.MethodsWe performed genetic analysis of BRAFV600E by PNA clamp real-time PCR in 211 PTCs in Korea, stratified by clinicopathological parameters.ResultsThe BRAFV600E mutation was detected in 90xa0% of PTC cases, and it occurred significantly more often in female patients than in male patients (pxa0=xa00.001). The clinicopathological parameters of age, tumor size, and disease stage were not associated with the BRAFV600E mutation, while extrathyroid invasion (pxa0=xa00.031), lymph nodal metastasis (pxa0=xa00.002), and tumor multiplicity (pxa0=xa00.020) were.ConclusionsThe prevalence (90xa0%) of the BRAFV600E mutation in this study is the highest ever reported, confirming the key role of this mutation in PTC tumorigenesis. The BRAFV600E mutation was associated with aggressive clinical behaviors including extrathyroid invasion, lymph nodal metastasis and tumor multifocality. The PNA clamp real-time PCR method for the BRAFV600E mutation detection is sensitive and is applicable in a clinical setting.

Characterization of aberrant FHIT transcripts in gastric adenocarcinomas

Aberrant transcripts of FHIT (fragile histidine triad) have been reported in several types of primary tumors and cell lines, including gastric carcinoma. The role of these aberrant transcripts in tumorigenesis is not clear yet. Forty-eight aberrant-sized FHIT transcripts with various lengths and number in 35 cases of gastric adenocarcinomas were further characterized. Aberrant transcripts, with deletions and/or insertions, were frequently observed in 20 cases of tumors. Sequence analysis demonstrated that different types of aberrant transcripts used normal splice sites but skipped exons, contained the inserts with the part of intron 5 sequences, or used the FHIT cDNA sequence 179-180 as a cryptic splice acceptor site. Most of aberrant transcripts lacked exon 5 and were presumably non-functional as the translation initiation codon is located in exon 5. Additionally, other transcripts, indicative of additional splice processing, either deletions or insertions, were expressed in several tumors. Taken together, our data indicate that the FHIT gene expression is frequently altered in gastric adenocarcinomas by aberrant splicing, and suggest that different types of aberrant transcripts may result during the multi-step splice processing.

Cyr61 Expression is associated with prognosis in patients with colorectal cancer

BackgroundCysteine-rich 61 (Cyr61), a member of the CCN protein family, possesses diverse functionality in cellular processes such as adhesion, migration, proliferation, and survival. Cyr61 can also function as an oncogene or a tumour suppressor, depending on the origin of the cancer. Only a few studies have reported Cyr61 expression in colorectal cancer. In this study, we assessed the Cyr61 expression in 251 colorectal cancers with clinical follow up.MethodsWe examined Cyr61 expression in 6 colorectal cancer cell lines (HT29, Colo205, Lovo, HCT116, SW480, SW620) and 20 sets of paired normal and colorectal cancer tissues by western blot. To validate the association of Cyr61 expression with clinicopathological parameters, we assessed Cyr61 expression using tissue microarray analysis of primary colorectal cancer by immunohistochemical analysis.ResultsWe verified that all of the cancer cell lines expressed Cyr61; 2 cell lines (HT29 and Colo205) demonstrated Cyr61 expression to a slight extent, while 4 cell lines (Lovo, HCT116, SW480, SW620) demonstrated greater Cyr61 expression than HT29 and Colo205 cell lines. Among the 20 cases of paired normal and tumour tissues, greater Cyr61 expression was observed in 16 (80%) tumour tissues than in normal tissues. Furthermore, 157 out of 251 cases (62.5%) of colorectal cancer examined in this study displayed strong Cyr61 expression. Cyr61 expression was found to be associated with pN (pu2009=u20090.018). Moreover, Cyr61 expression was associated with statistically significant cancer-specific mortality (pu2009=u20090.029). The duration of survival was significantly lesser in patients with Cyr61 high expression than in patients with Cyr61 low expression (pu2009=u20090.001). These results suggest that Cyr61 expression plays several important roles in carcinogenesis and may also be a good prognostic marker for colorectal cancer.ConclusionsOur data confirmed that Cyr61 was expressed in colorectal cancers and the expression was correlated with worse prognosis of colorectal cancers.

Expression of the survivin-2B splice variant related to the progression of colorectal carcinoma

Purpose Recently, two alternatively spliced survivin variants, survivin-ΔEx3 and survivin-2B, were identified in a single copy of the survivin gene. It has been reported that the expressions of survivin splice variants significantly correlates with the clinical results in many types of human carcinoma. We investigated the transcription levels of survivin and its splice variants in human colorectal carcinomas, and analyzed correlations between survivin expression levels and clinicopathologic features. Methods We used Western blot and real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) to analyze the protein and mRNA expression levels of survivin variants in 51 colorectal carcinomas. The quantitative RT-PCR was performed using primer pairs specific for survivin and each of its splice variants, then normalized for the gene that encodes glyceraldehydes-3-phosphate dehydrogenase. Results In Western blotting, the protein levels of survivin were higher in the tumor tissue than in normal tissue. The expression of survivin, survivin-2B and survivin-ΔEx3 mRNA was present in 96%, 64.7%, and 82.4% of the samples, respectively. When the pathologic parameters were compared, colorectal cancers of advanced pT stages showed significant decrease in survivin-2B mRNA expression by the quantitative RT-PCR (P < 0.001). Conclusion The decreased expression of survivin-2B might be related to tumor progression in colorectal cancers. This finding indicates that alternatively spliced variants of survivin may be involved in refining the functions of survivin during tumor progression.

Correlation between Liver Metastases and the Level of PRL-3 mRNA Expression in Patients with Primary Colorectal Cancer.

Purpose Phosphatase of regenerating liver-3 (PRL-3) has been associated with metastasis promotion. However, clinical applications of this association have not yet been clearly demonstrated. In this study, we evaluated the relation of PRL-3 mRNA level in primary colorectal cancer to the corresponding stage and to other clinicopathologic factors. Methods Two hundred forty-five patients with histologically-proven colorectal cancer underwent surgery between January 2004 and December 2006. RNA was extracted and cDNA was prepared by using reverse transcription. Quantification of PRL-3 was done using a real-time polymerase chain reaction. Results Eighty-six cases with well-preserved specimens were enrolled: 53 males and 33 females. The mean age was 63.4 years. According to tumour node metastasis (TNM) stage of the American Joint Committee on Cancer (AJCC), stage I was 11 cases, stage II was 38 cases, stage III was 23 cases, and stage IV was 14 cases. Among stage IV cases, one case was combined with liver and lung metastases, and one case was combined with liver metastases and peritoneal dissemination. The remaining stage IV patients were combined with only liver metastases. There was a significant correlation in PRL-3 mRNA expression between primary colorectal cancer and corresponding tumor stage. PRL-3 mRNA expression was increased in the liver metastases cases. Lymphatic and vascular invasion were significantly related with PRL-3 mRNA levels. Conclusion Advanced stage prediction may be obtained by measuring the level of PRL-3 mRNA expression in primary colorectal cancer. Especially, the risk of liver metastases may be predicted by measuring the level of PRL-3 mRNA expression in primary colorectal cancer. Further study is required to confirm these preliminary results.

Q787Q EGFR Polymorphism as a Prognostic Factor for Lung Squamous Cell Carcinoma

Objective: EGFR genetic polymorphisms have been investigated for carcinogenesis in various tumors including lung cancer. We evaluated EGFR mutations in four exons, with an emphasis on the Q787Q EGFR polymorphism in non-small-cell lung cancer. Methods: To determine the presence of the Q787Q polymorphism in patients with lung cancer, we performed direct sequencing analyses of four exons for 83 squamous cell carcinomas and 80 adenocarcinomas untreated with EGFR tyrosine kinase inhibitors. Results: The Q787Q EGFR polymorphism was more frequently detected in squamous cell carcinoma patients than in adenocarcinoma patients (24 vs. 15.9%). The group of patients with the Q787Q EGFR polymorphism included more males and heavy smokers compared with other patient groups. The presence of the Q787Q EGFR polymorphism significantly and negatively affected the overall survival rate among patients with non-small-cell carcinoma (p = 0.011), particularly those with squamous cell carcinoma (p = 0.037). Among stage I and II squamous cell carcinoma patients, those with the Q787Q EGFR polymorphism had a poor prognosis (p = 0.032). Conclusions: The Q787Q EGFR polymorphism allows stratifying lung squamous cell carcinoma patients and could be an independent prognostic marker, particularly among those in stages I and II.

RhoA is associated with invasion and poor prognosis in colorectal cancer.

Colorectal cancer is one of the most common cancers and is the fourth leading cause of cancer death in Korea. Mortality of colorectal cancer is strongly associated with the metastatic spread of the disease. As such, it is important to find and characterize signaling pathways involved in colon cancer metastasis. We investigated the functional importance of RhoA using human cell lines as well as 150 colorectal cancer patient-derived samples as it remains unclear whether RhoA functions as either an oncogene or a tumor suppressor in colon cancer. RhoA was highly expressed in metastatic cancer cell lines. Although cancer cell proliferation was only moderately impaired after depletion of RhoA, RhoA-depleted cancer cells exhibited markedly reduced migration and invasion ability in vitro. Furthermore, we found that RhoA is associated with the invasion of lymph nodes and blood vessels in the patient colorectal cancer samples. Most notably, patients with higher RhoA expression had a significantly poorer 5-year survival rate after surgery. These results suggest that RhoA is a marker of poor prognosis in colorectal cancer and may be a promising target for cancer treatment.

Karyopherin α-2 is a reliable marker for identification of patients with high-risk stage II colorectal cancer

PurposeAdjuvant chemotherapy (AC) is frequently considered in patients with high-risk stage II colorectal cancer (CRC). Among patients with stage II CRC who do not receive AC because they are not considered to be at high risk, 20–25% will develop recurrence and die from the disease. Elevated levels of KPNA2 have been observed in various cancers, and overexpression of KPNA2 is related to CRC progression.MethodsWe examined the expression of KPNA2 using 293 CRC tissues, including 118 with stage II CRC, and investigated the applicability of KPNA2 as a biomarker to predict high-risk stage II CRC. Moreover, we further investigated the role of KPNA2 as an oncogene in CRC carcinogenesis using in vitro functional studies.ResultsHigh KPNA2 expression was associated with vascular (pxa0=xa00.027) and lymphatic invasion (pxa0=xa00.009) in patients with stage II CRC. On multivariate analysis, high KPNA2 expression (HR 3.174, 95% CI 2.060–4.889; pxa0<xa00.001) was independently associated with survival in patients with CRC. The overall survival rate in patients with high KPNA2 expression was higher than that in patients with low KPNA2 expression in CRC (pxa0<xa00.001), even in patients with stage II CRC (pxa0=xa00.001). Additionally, KPNA2 was associated with tumorigenesis and cancer progression in CRC cells; high KPNA2 expression was associated with increased cell proliferation (pxa0<xa00.05), migration (pxa0=xa00.03), invasion (pxa0=xa00.001), and semisolid agar colony formation (pxa0<xa00.001).ConclusionKPNA2 expression is useful for identification of patients with high-risk stage II CRC who could benefit from AC and that KPNA2 may also be a promising therapeutic target.

Stromal-cell-derived Factor 1-α Promotes Tumor Progression in Colorectal Cancer

Purpose Although stromal-cell-derived factor (SDF)-1α is suggested to be involved in tumorigenicity and tumor angiogenesis, the clinicopathological significance of its expression in colorectal cancers is not fully understood. We examined SDF-1α expression in colorectal cancers and investigated its relationship to clinicopathological features such as tumor staging, lymph-node metastasis, vascular invasion (VI), lymphatic invasion (LI) and neural invasion (NI). Methods Specimens of 83 primary colorectal cancers were examined immunohistochemically, and the relationships between clinicopathological features and SDF-1α expression were analyzed. To compare the expressions between the normal colon tissue and colorectal cancer tissues, we performed Western blot analyses. Results According to the Western blot analyses, SDF-1α was more highly expressed in colorectal carcinoma tissues than in normal colonic mucosa (20/21). According to the immunohistochemical stain, SDF-1α was associated with nodal status, distant metastasis, tumor staging, VI and LI. SDF-1α expression had a significant prognostic value for overall survival. Kaplan-Meier plots of survival in patients with high SDF-1α showed that high SDF-1α expression was associated with a shorter overall survival. However, no association was found between SDF-1α expression and other pathologic or clinical variables, including age, gender, degree of differentiation, and presence of perineural invasion. Conclusion The expression of SDF-1α might be associated with tumor progression in colorectal cancer. Inhibition of SDF-1α could be a therapeutic option in colorectal cancer patients.

Protein kinase, membrane‑associated tyrosine/threonine 1 is associated with the progression of colorectal cancer

The protein kinase, membrane‑associated tyrosine/threoninexa01 (PKMYT1) is known to inhibit precocious entry into mitosis by phosphorylating CDK1 at Thr14 and Tyr15 residues. However, the functional importance of PKMYT1 in colorectal cancer (CRC) remains unknown. Thus, it is important to elucidate whether PKYMT1 is indispensable in the tumorigenesis of CRC. To investigate the functional importance of PKMYT1 in CRC tumorigenesis, PKMYT1 was knocked down in CRC cell lines such as SW480, SW620, HCT116 and HT29 by siRNA. PKMYT1‑depleted CRC cells were analyzed to determine proliferation, migration, invasion and colony forming ability. In addition, 179xa0patient‑derived samples were used to find the correlation of the expression of PKMYT1 with the prognosis of CRC patients. By siRNA‑mediated loss of function of PKMYT1, we observed that proliferation, migration, invasion and colony forming ability of CRC cell lines were significantly impaired in the absence of PKMYT1 inxa0vitro. Furthermore, by analyzing patient‑derived samples, we revealed the association of PKMYT1 with the overall survival rate of CRC patients. These results indicated that PKMYT1 plays an essential oncogenic role in CRC and could serve as a good therapeutic target for the treatment of CRC.