Yosuke Seki

Feasibility of a Lateral Region Sentinel Node Biopsy of Lower Rectal Cancer Guided by Indocyanine Green Using a Near-Infrared Camera System

A lateral pelvic lymph node dissection (LPLD) for lower rectal cancer may be beneficial for a limited number of patients. If sentinel node (SN) navigation surgery could be applied to lower rectal cancer, then unnecessary LPLDs could be avoided. The aim of this study was to investigate the feasibility of lateral region SN biopsy by means of indocyanine green (ICG) visualized with a near-infrared camera system (Photodynamic Eye, PDE). This study investigated the existence of a lateral region SN in 25 patients with lower rectal cancer. ICG was injected around the tumor, and the lateral pelvic region was observed with PDE. With PDE, the lymph nodes and lymph vessels that received ICG appeared as shining fluorescent spots and streams in the fluorescence image. This allowed the detection of not only tumor-negative SNs but also tumor-positive SNs as shining spots. The lateral SNs were detected in 6 of 6 T1 and T2 diseases and 17 of 19 T3 diseases. The lateral SNs were successfully identified in 23 (92%) of the 25 patients. The mean number of lateral SNs per patients was 2.1. Of the 23 patients, 6 patients underwent LPLD. Of the 3 patients who had a tumor-negative SN, all dissected lateral non-SNs were negative in all 3 cases. We could detect the lateral SNs, not only in T1 and T2 disease, but also in T3 disease. Although this is only a preliminary study, the detection of lateral SNs in lower rectal cancer by means of the ICG fluorescence imaging system is considered to be a promising technique that may be used for determining the indications for performing LPLD.BackgroundA lateral pelvic lymph node dissection (LPLD) for lower rectal cancer may be beneficial for a limited number of patients. If sentinel node (SN) navigation surgery could be applied to lower rectal cancer, then unnecessary LPLDs could be avoided. The aim of this study was to investigate the feasibility of lateral region SN biopsy by means of indocyanine green (ICG) visualized with a near-infrared camera system (Photodynamic Eye, PDE).MethodsThis study investigated the existence of a lateral region SN in 25 patients with lower rectal cancer. ICG was injected around the tumor, and the lateral pelvic region was observed with PDE.ResultsWith PDE, the lymph nodes and lymph vessels that received ICG appeared as shining fluorescent spots and streams in the fluorescence image. This allowed the detection of not only tumor-negative SNs but also tumor-positive SNs as shining spots. The lateral SNs were detected in 6 of 6 T1 and T2 diseases and 17 of 19 T3 diseases. The lateral SNs were successfully identified in 23 (92%) of the 25 patients. The mean number of lateral SNs per patients was 2.1. Of the 23 patients, 6 patients underwent LPLD. Of the 3 patients who had a tumor-negative SN, all dissected lateral non-SNs were negative in all 3 cases.ConclusionsWe could detect the lateral SNs, not only in T1 and T2 disease, but also in T3 disease. Although this is only a preliminary study, the detection of lateral SNs in lower rectal cancer by means of the ICG fluorescence imaging system is considered to be a promising technique that may be used for determining the indications for performing LPLD.

Comprehensive Clinico-Glycomic Study of 16 Colorectal Cancer Specimens: Elucidation of Aberrant Glycosylation and Its Mechanistic Causes in Colorectal Cancer Cells

The structures of neutral and acidic glycosphingolipids from both normal colorectal epithelial cells and colorectal cancer cells, which were highly purified with the epithelial cell marker CD326, have been analyzed. The analysis was performed on samples from 16 patients. The carbohydrate moieties from glycosphingolipids were released by endoglycoceramidase II, labeled by pyridylamination, and identified using two-dimensional mapping and mass spectrometry. The structures from normal colorectal epithelial cells are characterized by dominant expression of neutral type-1 chain oligosaccharides. Three specific alterations were observed in malignant transformation; increased ratios of type-2 oligosaccharides, increased alpha2-3 and/or alpha2-6 sialylation and increased alpha1-2 fucosylation. Although the degree of alteration varies case to case, we found that two characteristic alterations tend to be associated with clinical features. One is a shift from type-1 dominant normal colorectal epithelial cells to type-2 dominant colorectal cancer cells. This shift was found in 5 patients having hepatic metastasis. The other is specific elevation of alpha2-3 sialylation observed in 2 cases exhibiting high serum levels of CA19-9. Examination of the activities of the related glycosyltransferases revealed that while some alterations could be accounted for by changes in the activities of related glycosyltransferases others could not. Although the number of cases analyzed is small, these findings provide valuable information which will help in the elucidation of the mechanism of synthesis of aberrant glycosylation and its involvement in cancer malignancy.

Long-term Prognostic Value of Conventional Peritoneal Lavage Cytology in Patients Undergoing Curative Colorectal Cancer Resection

PURPOSE: Free malignant cells in the peritoneal cavity might play a role in the metastasis process. However, this phenomenon needs further elucidation. The aims of this study were to investigate the frequency of free cancer cells detected on cytologic examination of lavage fluid after peritoneal washing in patients undergoing curative surgery for colorectal cancer, to explore risk factors for exfoliation of cancer cells into the peritoneal cavity, and to evaluate the influence peritoneal lavage cytology as a prognostic tool. METHODS: Peritoneal lavage was performed in 697 patients undergoing curative resection of colorectal cancer. Before the manipulation of the tumor, 100 mL of physiologic saline solution was administered into the abdominal cavity and the fluid was collected for cytologic examination. Specimens were classified as positive if at least one cancer cell was detected. RESULTS: The mean follow-up period was 90.5 months. Overall, 15 (2.2%) of the 697 patients had positive results. Four characteristics were identified as risk factors for exfoliation of cancer cells into the peritoneal cavity: 1) depth of invasion, 2) regional lymph nodes, 3) lymphatic invasion, and 4) venous invasion. In univariate analyses of all 697 patients and the subgroup of 374 patients with pT3 or T4 tumors, patients with positive cytology findings had significantly worse disease-free and cancer-specific survival than patients with negative cytology findings (P < 0.001). On multivariate analysis, peritoneal cytology remained an independent predictor of cancer-specific survival in all patients and in patients with pT3 or pT4 tumors. Only peritoneal cytology was a significant prognostic factor for peritoneal recurrence (P < 0.0001). CONCLUSION: Conventional peritoneal cytology is a useful prognostic tool in patients undergoing curative surgery for colorectal cancer and may be helpful in making decisions whether to select intraperitoneal or systemic chemotherapy.

Role of p21waf1/cip1 in effects of oxaliplatin in colorectal cancer cells

Clinical studies have shown that oxaliplatin, a novel platinum derivative, is a potent chemotherapeutic agent for colorectal cancer when combined with 5-fluorouracil and leucovorin. Although the toxic activity is based on covalent adducts between platinum and DNA, its actual biological behavior is mostly unknown. In an effort to explore the mechanism of tumor susceptibility to oxaliplatin, we examined the cytotoxic effects of oxaliplatin in colorectal cancer cell lines in reference to p53 gene status. Although p53 gene status did not clearly predict sensitivity to oxaliplatin, p53 wild-type cells including HCT116 were sensitive but HCT116 p53−/− were found to be resistant to oxaliplatin. Oxaliplatin caused strong p21waf1/cip1 induction and G0-G1 arrest in p53 wild-type cells, whereas cisplatin did not induce G0-G1 arrest. Assays using p53 wild but p21waf1/cip1 null HCT116 cells revealed that oxaliplatin did not show G0-G1 arrest and reduced growth-inhibitory effects, suggesting that p21waf1/cip1 may be a key element in oxaliplatin-treated p53 wild-type cells. Although HCT116 is DNA mismatch repair–deficient, a mismatch repair–proficient HCT116+ch3 cell line displayed similar responses with regard to p21waf1/cip1-mediated growth inhibition and G0-G1 arrest. In p53 mutant cells, on the other hand, oxaliplatin caused an abrupt transition from G1 to S phase and eventually resulted in G2-M arrest. This abrupt entry into S phase was associated with loss of the p21waf1/cip1 protein via proteasome-mediated degradation. These findings suggest that p21waf1/cip1 plays a role in oxaliplatin-mediated cell cycle and growth control in p53-dependent and -independent pathways.

Construction of a novel DNA decoy that inhibits the oncogenic β-catenin/T-cell factor pathway

The oncogenic β-catenin/T-cell factor (TCF) signal is a common trigger inducing expressions of various cancer-related genes and is activated in various types of human malignancy. The aim of this study was to create an effective double-stranded DNA decoy that would interfere with endogenous TCF hyperactivity in tumor cells. We first established the TCF-activated model using nontumor human embryonic kidney 293 (HEK293) cells by introducing a β-catenin cDNA. Based on a consensus TCF-binding sequence in the cyclin D1 and c-myc promoters, several double-stranded oligodeoxynucleotides were designed and tested for their ability to inhibit TCF activity in the HEK293 model. Among them, the 18-mer oligodeoxynucleotide stably formed double-stranded DNA and efficiently inhibited TCF activity. FITC-labeled oligodeoxynucleotide was efficiently incorporated into the nucleus at 6 hours and remained within cells for up to 72 to 96 hours. When compared with scrambled oligodeoxynucleotide, we found that the 18-mer TCF decoy significantly inhibited TCF activity and promoter activities of the downstream target genes, such as cyclin D1, c-myc, and matrix metalloproteinase 7 in HCT116 colon cancer cells. Reverse transcription-PCR assays indicated that mRNA expression of these genes decreased with treatment of the TCF decoy. Proliferation assay showed that the TCF decoy significantly inhibited growth of HCT116 tumor cells, but not of nontumor HEK293 cells. Our data provide evidence that the TCF decoy reduced both TCF activity and transcriptional activation of downstream target genes. Thus, this TCF decoy is potentially an efficient and nontoxic molecular targeting therapy for controlling malignant properties of cancer cells. [Mol Cancer Ther 2006;5(4):985–94]

Second Primary Cancer in Patients with Colorectal Cancer after a Curative Resection

Background: Colorectal cancer (CRC) patients have an increased risk of developing other malignancies. Understanding the characteristics of the second primary cancer is important to establish an effective surveillance program. Methods: This study investigated 301 CRC patients to assess the risk factors for postoperative primary cancers arising from organs distinct from the colorectal area (extracolorectal cancers). The observed/expected ratio (O/E ratio) was calculated using the Osaka Cancer Registry, to determine the rate of increase in extracolorectal cancers. Results: The frequency of postoperative extracolorectal cancers was 12.6%. A logistic regression analysis showed only age to be an independent risk factor for postoperative extracolorectal cancer development. The O/E ratio of overall postoperative extracolorectal cancer was significantly higher than one (O/E ratio 2.6, p < 0.01). In each organ, the frequency of lung and gastric cancers were significantly higher than one, with O/E ratios of 3.2 and 2.7 (p < 0.01 and p < 0.05, respectively). Conclusion: The frequency of postoperative extracolorectal cancers in CRC patients was significantly higher than that in the normal population, especially for lung and gastric cancers. Clinicians should carefully follow patients for a possible recurrence of CRC and educate CRC patients with regard to the high risk of a second primary cancer.

Presence of minute cancer cell dissemination in peritoneal lavage fluid detected by reverse transcription PCR is an independent prognostic factor in patients with resectable pancreatic cancer.

BACKGROUND Presence of minute cancer cell dissemination in peritoneal lavage fluid detected by reverse transcription polymerase chain reaction (RT-PCR) has been reported to be a reliable predictor of the prognosis in several kinds of cancers, but has not been determined in pancreatic cancer. METHODS Peritoneal lavage fluid was harvested just after a laparotomy in 83 patients with adenocarcinoma of the pancreas. Half of the fluid was examined by cytology and the remaining half was used to measure carcinoembryonic antigen/beta-2-microglobulin (beta2M) mRNA expression. Patients were followed after surgery to evaluate its clinical significance. RESULTS Among 83 patients, 3 were cytologically positive (CY+), while 23 were positive by RT-PCR (PCR+). Seventy-one patients underwent a surgical resection whereas 12 were unresectable. Because 2 were CY+ among the 71 operated patients, the remaining 69 CY- patients were further investigated. Among those 69 patients, PCR+ was observed in 15 patients, whose incidence of postoperative peritoneal recurrence was significantly higher than that in PCR- patients (21% vs 4% at 3 years; P = .039). Moreover, both the recurrence-free rate in the abdominal cavity (peritoneal or local recurrence, excluding liver metastases) and the overall survival rate were better in PCR- patients than PCR+ patients (78% vs 33%, P = .0045 and 67% vs 46%, P = .0151). A multivariate analysis revealed positive lymph node metastases (hazard ratio; 5.18) and positive RT-PCR (hazard ratio; 3.65) were independent prognostic factors. CONCLUSION The RT-PCR-based cancer cell detection was an independent prognostic factor in patients with resectable adenocarcinoma of the pancreas and had close association with local or peritoneal recurrence.

Doubling Time of Carcinoembryonic Antigen Is a Significant Prognostic Factor after the Surgical Resection of Locally Recurrent Rectal Cancer

Background: Patients undergoing a curative rectal cancer resection have a risk of developing locoregional recurrence. A curative resection for local recurrence is the option of improvement in prognosis. However, a curative resection is sometimes too invasive and should be considered in selected patients. Methods: A total of 43 patients with locally recurrent rectal cancer who had been treated by operation between 1989 and 2007 were retrospectively reviewed and the factors, including doubling time of carcinoembryonic antigen (CEA-dt), were analyzed. Results: The 5-year overall survival rate after the operation for local recurrence was 50.8%. Gender, presence of distant metastasis, tumor size, CEA-dt and curability were found to be significant prognostic factors. A multivariate analysis demonstrated the presence of distant metastasis, CEA-dt and tumor size to be significant prognostic factors for overall survival. The 5-year overall survival rates of patients with a CEA-dt ≧150 days and a tumor size <5 cm were 76.9%. Conclusions: The tumor size and CEA-dt were useful prognostic factors that were recognizable before surgery. Patients with locally recurrent rectal cancer with a CEA-dt ≧150 days and a recurrent tumor size <5 cm are considered to be good candidates for surgery.

Gastric Fluid Volume Change After Oral Rehydration Solution Intake in Morbidly Obese and Normal Controls: A Magnetic Resonance Imaging–Based Analysis

BACKGROUND: Although preoperative fluid intake 2 hours before anesthesia is generally considered safe, there are concerns about delayed gastric emptying in obese subjects. In this study, the gastric fluid volume (GFV) change in morbidly obese subjects was investigated after ingesting an oral rehydration solution (ORS) and then compared with that in nonobese subjects. METHODS: GFV change over time after the ingestion of 500 mL of ORS containing 2.5% carbohydrate (OS-1) was measured in 10 morbidly obese subjects (body mass index [BMI], >35) scheduled for bariatric surgery and 10 nonobese (BMI, 19–24) using magnetic resonance imaging. After 9 hours of fasting, magnetic resonance imaging scans were performed at preingestion, 0 min (just after ingestion), and every 30 minutes up to 120 minutes. GFV values were compared between morbidly obese and control groups and also between preingestion and postingestion time points. RESULTS: The morbidly obese group had a significantly higher body weight and BMI than the control group (mean body weight and BMI in morbidly obese, 129.6 kg and 46.3 kg/m2, respectively; control, 59.5 kg and 21.6 kg/m2, respectively). GFV was significantly higher in the morbidly obese subjects compared with the control group at preingestion (73 ± 30.8 mL vs 31 ± 19.9 mL, P = .001) and at 0 minutes after ingestion (561 ± 30.8 mL vs 486 ± 42.8 mL; P < .001). GFV declined rapidly in both groups and reached fasting baseline levels by 120 minutes (morbidly obese, 50 ± 29.5 mL; control, 30 ± 11.6 mL). A significant correlation was observed between preingestion residual GFV and body weight (r = .66; P = .001). CONCLUSIONS: Morbidly obese subjects have a higher residual gastric volume after 9 hours of fasting compared with subjects with a normal BMI. However, no differences were observed in gastric emptying after ORS ingestion in the 2 populations, and GFVs reached baseline within 2 hours after ORS ingestion. Further studies are required to confirm whether the preoperative fasting and fluid management that are recommended for nonobese patients could also be applied to morbidly obese patients.

Genome-wide DNA methylation analysis during non-alcoholic steatohepatitis-related multistage hepatocarcinogenesis: Comparison with hepatitis virus-related carcinogenesis

Summary Genome-wide DNA methylation analysis indicated that DNA methylation alterations are already present even at the precancerous NASH stage, clearly differing from such alterations in viral hepatitis or cirrhosis, and possibly continuing to participate in NASH-related multistage hepatocarcinogenesis.