Jen-Kou Lin

Expression of β-F1-ATPase and mitochondrial transcription factor A and the change in mitochondrial DNA content in colorectal cancer: clinical data analysis and evidence from an in vitro study

PurposeMitochondria play an important role in regulating apoptosis and thus may be involved in tumor progression. This study was conducted to elucidate the role of mitochondrial dysfunction in colorectal cancer (CRC).MethodsMitochondrial DNA (mtDNA) content was analyzed with real-time polymerase chain reaction in 153 CRC patients who had received surgery at the Taipei Veterans General Hospital from January 1999 to December 2000. The expression of mitochondrial transcription factor A (TFAM) and β-F1-ATPase were analyzed using immunohistochemistry. HCT116 cells were cultured in 1% O2 for at least 20 passages. Mitochondrial biogenesis, ATP production, and the apoptotic response to 5-fluorouracil were analyzed in the derived cells.ResultsDisease stage was associated with changes in mtDNA content (pu2009<u20090.001), expression of TFAM (pu2009=u20090.004), and/or β-F1-ATPase (pu2009<u20090.001). CRCs with low expression of TFAM or β-F1-ATPase had a lower mtDNA content. In the multivariate analysis, disease stage was the most significant prognostic factor [95% confidence interval (CI), 2.82–6.23], followed by β-F1-ATPase [95% CI, 1.10–4.10]. In patients receiving 5-FU based chemotherapy, the 5-year disease-free survival rate was only 27% in CRC patients with a low β-F1-ATPase tumor and was significantly lower than that in those with a high β-F1-ATPase tumor (60%; pu2009=u20090.042). In the hypoxia-treated cells, mitochondrial mass increased, mtDNA content decreased, sensitivity to 5-fluorouracil decreased, and β-F1-ATPase expression decreased.ConclusionMitochondrial dysfunction may be associated with poor outcomes in CRC patients.

Mitochondrial D-loop mutation is a common event in colorectal cancers with p53 mutations

Purposep53 is the most frequently mutated gene in colorectal cancer. In mitochondria, p53 protein is involved in regulation of transcription/replication and maintenance of genomic stability. Our aim was to examine the relationship between p53, D-loop mutation, and mitochondrial DNA content in colorectal cancer (CRC).MethodsA total of 194 patients with sporadic CRC without microsatellite instability who underwent surgery in Taipei Veterans General Hospital from January 1999 to December 2000 were included. The mitochondrial DNA content and D-loop mutation were quantified using real-time PCR and sequencing.ResultsD-loop mutation occurred at significantly higher frequency in tumors with p53 mutation (34/88; 38.6%) than in tumors without p53 mutation (23/106; 21.7%). The frequency of the decreased mtDNA content was significantly associated with TNM stage (pu2009=u20090.009) and p53 mutation (pu2009=u20090.036). The 5-year DFS rate was 39% in patients exhibiting tumors with decreased mtDNA content, and was significantly poorer in these patients than in those exhibiting tumors with normal level of mtDNA content (61%, pu2009=u20090.01). The presence of D-loop mutations had no effect on 5-year DFS rate. In multivariate survival analysis, TNM stage, and p53 mutation, but not decreased mtDNA content and D-loop instability, had significant impacts on prognosis.ConclusionChange of mitochondrial DNA is a common event in colorectal cancer with p53 mutation, but is not associated with prognosis of CRC patients.

Early postoperative CEA level is a better prognostic indicator than is preoperative CEA level in predicting prognosis of patients with curable colorectal cancer

PurposeCarcinoembryonic antigen (CEA) measurements performed preoperatively and during the early postoperative period were examined prospectively to assess their prognostic value for colorectal cancer (CRC) patients receiving curative surgery.MethodsBetween 2000 and 2004, 1,361 patients with CRC who underwent curative surgery at the Taipei Veterans General Hospital were enrolled prospectively. CEA was measured prior to surgery and during the third or fourth postoperative week. The endpoint was length of postoperative disease-free survival, and prognostic importance was determined using the log-rank test and Cox regression hazard model.ResultsSix hundred (44.1%) CRC patients had high CEA concentrations preoperatively, and 188 (13.8%) patients retained high values postoperatively. Within the median follow-up period of 61 (6–108) months, CRC recurred in 313 patients. By univariate analysis TNM staging, tumor differentiation, lymphovascular invasion, preoperative CEA concentration, and postoperative CEA concentration affected the outcome. By multivariate analysis, the prognostic importance of postoperative CEA was retained (95% CI, 1.73–3.01; HRu2009=u20092.28) but that of preoperative CEA was lost (95% CI, 0.82–1.33; HRu2009=u20091.05). CRC recurred earlier in patients with high postoperative CEA concentrations; metastasis to the liver was common (72.3%) among patients in this group.ConclusionsEarly postoperative CEA concentration is an independent prognostic factor for CRC. Patients with high postoperative CEA values should receive aggressive follow-up examinations for early relapse of CRC, with special attention paid to recurrence at the liver.

Nuclear expression of CXCR4 is associated with advanced colorectal cancer.

Background and objectivesCXCR4 and its ligand, SDF-1α, play an important role in the targeted metastasis of colon cancer. In this study, we analyzed an expression of CXCR4 in clinical samples and showed that SDF-1α affected the expression of CXCR4 in colon cancer cells.Materials and methodsA total of 388 patients with colorectal cancer (CRC) who underwent surgery in Taipei Veterans General Hospital from 2000 to 2004 were included. The expression of CXCR4 in CRC was visualized by immunohistochemistry (anti-CXCR4 mAb, R&D 12G5). HCT116, SW480, and SW620 cells were treated with SDF-1α in vitro and the CXCR4 proteins located in the cytoplasmic and nuclear compartments were separated and analyzed with western blotting.ResultsThe frequency of cytoplasmic and nuclear expression of CXCR4 in colorectal cancers was 35.6% and 36.9%, respectively. Nuclear but not cytoplasmic expression of CXCR4 was associated with advanced CRC (pu2009<u20090.001) and lymphovascular invasion. However, in multivariate analysis, nuclear expression of CXCR4 did not correlate with patients outcome. In the in vitro study, SDF-1α, stimulation of three colorectal carcinoma lines enhanced the CXCR4 nuclear expression.ConclusionExpression of the CXCR4 plays a role in CRC progression and may be associated with SDF-1α stimulation.

Role of MTHFR polymorphisms and folate levels in different phenotypes of sporadic colorectal cancers

Background and aimsBy altering both DNA methylation and nucleotide synthesis, folate metabolism is thought to contribute to colorectal carcinogenesis. We examined the role of folate metabolism in three different phenotypes of sporadic colorectal cancers (CRCs), phenotypes that were classified by the status of microsatellite instability (MSI) and chromosomal instability (CIN): MSI-H, microsatellite stability (MSS)/aneuploidy, and MSS/diploid.Patients and methodsA total of 195 sporadic colorectal tumors and another 195 age- and gender-matched healthy volunteers in Taipei-Veteran General Hospital and Taipei City Hospital were collected. We analyzed for MTHFR (methylenetetrahydrofolate reductase) polymorphisms (C677T, A1297C), folate, and vitamin B12 levels. We determined MSI status and DNA ploidy with fluorescent polymerase chain reaction and flow cytometry. Relations between clinicopathological variables and molecular variables were analyzed by χ2 tests (with Yates’ correction) for categorical variables and Student’s t test for numerical variables.ResultsFolate levels (5.02±4.43xa0ng/ml) were significantly lower in cancer patients than in controls (7.22±4.46xa0ng/ml). Vitamin B12 level was similar between cancer patients and controls. The frequency of the TT genotype of MTHFR C627T (12.3%) was slightly higher than controls (8.2%), but it did not reach statistical significance (p=0.174). Within the low-folate group (<5xa0ng/ml), the frequency of the TT genotype in cancer patients (14.4%) was significantly higher than in controls (4.6%). Sixteen patients who had MSI-H CRC (8.2%) had a significantly higher frequency of TT MTHFR (37.5%) and lower folate levels (3.56±2.41xa0ng/ml) than patients with MSS tumors (10.1%, 5.14±3.72xa0ng/ml). Patients with MSS/aneuploid tumors had significantly lower folate levels (4.50±3.06xa0ng/ml) than those with MSS/diploid tumors (6.69±4.73xa0ng/ml).ConclusionFolate deficiency and the MTHFR genetic polymorphism play an important role in colorectal carcinogenesis, including MSI and CI.SynopsisFolate metabolism plays an important role in colorectal carcinogenesis. We demonstrate that patients with MSI-H tumors had higher frequency of TT MTHFR C627T (37.5%), and patients with MSS/aneuploid tumor had lower folate level (4.50±3.06xa0ng/ml).

Risk and patterns of brain metastases in colorectal cancer

PURPOSE: In patients with colorectal cancer, brain metastasis is infrequent. This study aims to elucidate the risk, pattern of occurrence, and survival time after different treatment modalities. METHODS: A retrospective review of all patients with colorectal cancer admitted to the Veterans General Hospital-Taipei between 1970 and 1996 from our hospital was performed. Univariate analysis for survival determination was performed. RESULTS: Brain metastases developed subsequent to surgery for colorectal cancer in 53 well-documented patients, at a median of 36 months after surgery. Brain metastases were more commonly seen in rectal cancer and often occurred concurrently with lung metastases. Forty of these patients received active intervention in terms of surgery, chemotherapy, or radiotherapy, with surgical intervention achieving a significantly increased mean survival time (± standard deviation) compared with chemotherapy or radiotherapy or both of 86.6±17.35vs. 2.9±0.59 months (P<0.05). CONCLUSION: Increased awareness of the possibility of brain metastases, early diagnosis, and aggressive therapy can provide increased survival time for patients with colorectal cancer with brain metastases.

Metachronous colorectal cancer: necessity of post-operative colonoscopic surveillance

Background and aimsThe aim of this study was to identify the occurrence and analyze the characteristics of metachronous colorectal cancers, and to compare the characteristics of these cases (index tumor) with the control group to find any predicting factor that may influence the occurrence of metachronous cancer.Patients and methodsThe database of colorectal cancer in the Veterans General Hospital-Taipei, from January 1981 to September 2001 was reviewed. In total, 3,846 cases of adenocarcinoma of the colon and rectum, which received curative resection during this period, were found. The criteria of metachronous cancer were: occurrence more than 12xa0months after curative surgery; with pre-operative complete colonoscopy or one negative post-operative colonoscopic follow-up to rule out synchronous tumor; tumor arising from mucosa at a site other than anastomosis. The age, gender of the patients, the location, pathological characteristics of the metachronous tumors, occurrence of associated adenomas, the number of lesions, and the tumor stage were analyzed and compared with the control group.ResultsIn total, 43 cases of metachronous cancer were identified, giving an annual incidence of 0.18%. The distribution of the location of the index tumor of metachronous cases was predominantly left-sided, which was not different from that of the control group. The mean duration of occurrence of metachronous cancer after the primary operation was 71±46.6xa0months. The association of adenomas had no relationship with the occurrence of the metachronous cancer. No significant predicting factors for the development of metachronous tumors were found.ConclusionLifelong regular post-operative colonoscopic surveillance is essential for colorectal cancer patients.

Impact of Circulating Free Tumor Cells in the Peripheral Blood of Colorectal Cancer Patients during Laparoscopic Surgery

Despite widespread use of laparoscopic surgery for colorectal operations, its application for curative resection of colorectal cancer is still controversial. One of the major concerns is the impact of the laparoscopic procedure on dissemination of tumor cells. The main purpose of this study was to investigate the impact of laparoscopic surgery on circulating tumor cells in colorectal cancer patients. Quantitation of circulating free tumor cells (FTCs) was performed preoperatively, during the operation, and 14 days later by means of real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) targeting guanylyl cyclase C (GCC) mRNA in 42 colorectal cancer patients undergoing laparoscopic resections. Despite an increasing trend of FTC detection in patients with advancing stage, there is no significant difference in the preoperative FTC level by disease stage. No elevation in FTC level was found during the laparoscopic procedure in most patients compared with their preoperative FTC value. Patients with a persistently high FTC load [per nucleated blood cells (NBCs)] (> 102 FTCs/106 NBCs) 2 weeks postoperatively portends a poor prognosis regarding disease recurrence and tumor-related mortality when compared to those with an undetectable or low FTC load (≤ 102 FTCs/106 NBCs). We concluded that the laparoscopic procedure itself had no significantly deleterious effect on circulating FTCs and that the detection of FTCs by real-time qRT-PCR might be of clinical importance during the postoperative follow-up for colorectal cancer patients.

Change in anal continence after surgery for intersphincteral anal fistula: a functional and manometric study.

AbstractnBackground and aims. Dividing or laying open of the tract for intersphincteral type anal fistula is simple and effective and entails low risk of complication, but little is known of the functional and manometric results. This study assessed the clinical and manometric effect of this surgery on anal sphincter function.nPatients and methods. The study examined 45 adults undergoing surgical treatment for intersphincteral fistula. We administered the questionnaire for continence score and performed anorectal manometry before the operation and at least 6xa0months after the operation. The operative method was laying open of the fistula tract and trimming the redundant anoderm for adequate drainage of the wound in all cases.nResults. There was a significant decrease in maximal resting anal pressure and in resting pressure throughout the distal 2xa0cm of the anal canal after operation. The maximal contractile pressure after operation was similar to that before operation. Continence control was significantly poorer in women and patients who had lower preoperative resting pressure. Multivariate analysis showed lower preoperative resting pressure to be the only independent factor for impaired continence control after fistula surgery.nConclusion. Although laying open of the fistula tract is a simple and effective therapy for intersphincteral type anal fistula, it should be more conservative for patients with low resting anal pressure.

Carbohydrate antigen 19-9 is a valuable prognostic factor in colorectal cancer patients with normal levels of carcinoembryonic antigen and may help predict lung metastasis

PurposeWe retrospectively analyzed preoperative levels of carbohydrate antigen (CA) 19-9 in colorectal cancer (CRC) patients to determine the prognostic value of CA19-9 in CRC patients with normal carcinoembryonic antigen (CEA) levels.MethodsA total of 639 patients who underwent curative surgery at Taipei Veterans General Hospital between 2002 and 2006 were enrolled. We excluded 254 patients (39.7xa0%) with high preoperative CEA levels and analyzed 385 patients with normal CEA levels. The measured endpoint was the postoperative disease-free survival (DFS). The prognostic value of CA19-9 was determined using log-rank test and Cox regression analysis.ResultsHigh CA19-9 levels were significantly associated with advanced disease and were detected in 5.8xa0% of patients with stage I disease, 11.7xa0% of those with stage II disease, and 22.5xa0% of those with stage III disease (Pu2009<u20090.001). The 5-year DFS in patients with normal CA19-9 levels was 82.0xa0%, which was significantly higher than that in patients with high CA19-9 levels (68xa0%; Pu2009<u20090.001). In a multivariate analysis, the most important independent factor affecting the 5-year DFS was tumor–node–metastasis stage (95xa0% CI, 1.26–2.36; HRu2009=u20091.72). After stratification by other factors, high CA19-9 level remained an independent prognostic factor for patients with normal CEA levels. Patients with high CA19-9 levels also showed a higher incidence of lung metastasis (23.1xa0%) than those with normal CA19-9 levels (7.2xa0%).ConclusionsCA19-9 may be a prognostic factor for CRC patients with normal CEA levels. An aggressive follow-up protocol for lung metastasis should be used for these patients.