Guichao Li

High-Performance Size-Based Microdevice for the Detection Of Circulating Tumor Cells from Peripheral Blood in Rectal Cancer Patients

Since individualized therapy becomes more and more important in the treatment of rectal cancer, an accurate and effective approach should be established in the clinical settings to help physicians to make their decisions. Circulating tumor cells (CTCs), originated from either primary or metastatic cancer, could provide important information for diagnosis and monitoring of cancer. However, the implication and development of CTCs are limited due to the extreme rarity of these tumor cells. In this study we fabricated a simple and high-performance microfluidic device, which exploited numerous filtered microchannels in it to enrich the large-sized target tumor cells from whole blood. A very high CTC capture efficiency (average recovery rate: 94%) was obtained in this device at the optimum flow rate of 0.5 mL/h and channel height of 5 µm. Additionally, we used this device for detecting CTCs in 60 patients with rectal cancer. The CTC counts of rectal cancer patients were significantly higher than those in healthy subjects. Furthermore, the CTC counts detected by this device were significantly higher than those by EpCAM bead-based method for rectal cancer patients with various stage. Especially, for localized rectal cancer patients, the positive rates of samples with more than 3 CTCs per 5 mL blood by use of microdevice vs. EpCAM-based ones were 100% vs. 47%, respectively. Thus, this device provides a new and effective tool for accurate identification and measurement of CTCs in patients with rectal cancer, and has broad potential in clinical practice.

Radiosensitization of Human Colorectal Cancer Cells by MLN4924: An Inhibitor of NEDD8-Activating Enzyme.

Colorectal cancer is the third most frequently diagnosed cancer and the combination of radiation with capecitabine has been shown to achieve only 15% to 25% of pathologic complete response. This study aimed to investigate the effect of MLN4924, a potent small molecule inhibitor of SKP1-Cullin-F-box proteins E3 ubiquitin ligases, as a novel radiosensitizing agent in colorectal cancer cells. Indeed, we found that MLN4924 effectively sensitized colorectal cancer cells to radiation with a sensitivity-enhancement ratio of 1.61 for HT-29 cells and 1.35 for HCT-116 cells. Mechanistically, MLN4924 significantly enhanced radiation-induced G2/M arrest, apoptosis, and DNA damage response through accumulation of p27. Knockdown of p27 via small interfering RNA partially inhibited MLN4924-induced radiosensitization, indicating a causal role played by p27. Our study suggested that MLN4924 could be further developed as a novel radiosensitizing agent against colorectal cancer.

The advantage of circulating tumor cells over serum carcinoembryonic antigen for predicting treatment responses in rectal cancer.

AIM The objective of this study was to investigate the clinical significance of circulating tumor cells (CTCs) on the evaluation and prediction of treatment responses in rectal cancer patients compared with serum carcinoembryonic antigen (CEA). MATERIALS & METHODS Both CTCs and CEA levels of 103 rectal cancer patients (66 with stage II-III and 37 with recurrence or metastasis) were analyzed before and after chemoradiotherapy. CTCs were detected using EpCAM magnetic bead-based enrichment combined with cytometric identification. RESULTS CTCs were detected in all patients while no tumor cells were found in healthy controls. CTC levels in metastatic patients were significantly higher than those with recurrence or stage II-III rectal cancer. There is a close relationship between CTC levels and treatment outcomes but serum CEA did not have any correlation. CONCLUSION CTCs are promising markers for the evaluation and prediction of treatment responses in rectal cancer patients, superior to the conventional tumor marker CEA.

Circulating tumor cells: A promising marker of predicting tumor response in rectal cancer patients receiving neoadjuvant chemo-radiation therapy

Purpose The aim of this study was to investigate the role of circulating tumor cells (CTCs) in assessing and predicting tumor response to neoadjuvant chemoradiotherapy (CRT) for patients with locally advanced rectal cancer (LARC). Methods A total of 115 patients with T3-4 and/or N+ rectal cancer were enrolled. All patients received neoadjuvant CRT followed by radical surgery after 6-8 weeks. The pathological results after surgery were evaluated according to tumor regression grade (TRG) classification. Results Based on TRG score, patients were classified as responders (TRG3-4) and non-responders (TRG0-2). The baseline CTC counts of responders were significantly higher than those of non-responders (44.50±11.94 vs. 37.67±15.45, P=0.012). By contrast, the post-CRT CTC counts of responders were significantly lower than those of non-responders (3.61±2.90 vs. 12.08±7.40, P<0.001). According to ROC analysis, Δ%CTC (percentage difference in CTC counts between baseline and post-CRT) was identified as the stronger predictor to discriminate responders from non-responders (AUC: 0.860). The results of multivariate analysis also indicated that post-CRT CTC counts and Δ%CTC were significantly and independently associated with tumor response to CRT. Conclusions The detection of CTCs is a powerful and promising tool for evaluating and predicting responses to neoadjuvant CRT in LARC patients.

Telomerase reverse transcriptase methylation predicts lymph node metastasis and prognosis in patients with gastric cancer

Purpose Telomerase activity is associated with cellular immortalization and is present in most human tumors but absent in normal tissues. The activity of telomerase reverse transcriptase (TERT), a catalytic telomerase subunit, correlates with telomerase activity in tumors. The objective of this study was to investigate TERT promoter methylation and its prognostic impact in gastric cancer (GC). Patients and methods The analysis of TERT promoter methylation was performed in tumors and corresponding normal tissues of 116 patients with GC using a highly sensitive Sequenom Epityper assay. The expression of TERT in GC tissues was measured by quantitative real-time polymerase chain reaction. Results The levels of TERT promoter methylation in GC samples were significantly higher than in normal adjacent tissues (P=0.002). Hypermethylation of TERT promoter was associated with high T-stage (P=0.024), late N-stage (P=0.006), and lymphovascular/neural invasion (P=0.035), without correlation with age, sex, or histological grade. Simple linear regression analysis showed that TERT mRNA correlated positively with TERT methylation (R2=0.562, P=0.001). Also, higher TERT mRNA expression was related to hypermethylation of TERT promoter in GC samples (P=0.005). Univariate analysis demonstrated that N-stage (P=0.002) and TERT promoter methylation (P=0.004) were predictive of overall survival. Furthermore, multivariate analysis confirmed that N-stage (P=0.013) and TERT promoter methylation (P=0.031) were independent prognostic indicators for overall survival. Conclusion Our data suggested that hypermethylation of TERT promoter may contribute to gastric wall invasion, lymph node metastasis, lymphovascular/neural invasion, and poor prognosis in GC. GC patients with hypermethylation of TERT promoter could be eligible for close follow-up.

Radiation-Induced Liver Injury in Three-Dimensional Conformal Radiation Therapy (3D-CRT) for Postoperative or Locoregional Recurrent Gastric Cancer: Risk Factors and Dose Limitations.

Purpose This study examined the status of radiation-induced liver injury in adjuvant or palliative gastric cancer radiation therapy (RT), identified risk factors of radiation-induced liver injury in gastric cancer RT, analysed the dose-volume effects of liver injury, and developed a liver dose limitation reference for gastric cancer RT. Methods and Materials Data for 56 post-operative gastric cancer patients and 6 locoregional recurrent gastric cancer patients treated with three-dimensional conformal radiation therapy (3D-CRT) or intensity-modulated radiation therapy (IMRT) from Sep 2007 to Sep 2009 were analysed. Forty patients (65%) were administered concurrent chemotherapy. Pre- and post-radiation chemotherapy were given to 61 patients and 43 patients, respectively. The radiation dose was 45–50.4 Gy in 25–28 fractions. Clinical parameters, including gender, age, hepatic B virus status, concurrent chemotherapy, and the total number of chemotherapy cycles, were included in the analysis. Univariate analyses with a non-parametric rank test (Mann–Whitney test) and logistic regression test and a multivariate analysis using a logistic regression test were completed. We also analysed the correlation between RT and the changes in serum chemistry parameters [including total bilirubin, (TB), direct bilirubin (D-TB), alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and serum albumin (ALB)] after RT. Results The Child-Pugh grade progressed from grade A to grade B after radiotherapy in 10 patients. A total of 16 cases of classic radiation-induced liver disease (RILD) were observed, and 2 patients had both Child-Pugh grade progression and classic RILD. No cases of non-classic radiation liver injury occurred in the study population. Among the tested clinical parameters, the total number of chemotherapy cycles correlated with liver function injury. V35 and ALP levels were significant predictive factors for radiation liver injury. Conclusions In 3D-CRT for gastric cancer patients, radiation-induced liver injury may occur and affect the overall treatment plan. The total number of chemotherapy cycles correlated with liver function injury, and V35 and ALP are significant predictive factors for radiation-induced liver injury. Our dose limitation reference for liver protection is feasible.

Postoperative Chemoradiotherapy Combined with Epirubicin-Based Triplet Chemotherapy for Locally Advanced Adenocarcinoma of the Stomach or Gastroesophageal Junction

Background Due to low tolerance to chemotherapy, the maximum number of cycles of postoperative adjuvant chemotherapy is 4 in adjuvant gastric clinical trials. The aim of this study is to retrospectively evaluate the safety and efficacy of adjuvant epirubicin-based triplet chemotherapy and radiotherapy in the treatment of resected locally advanced stomach or gastroesophageal junction adenocarcinoma. Methodology/Principal Findings From January 2004 to July 2008, ninety-seven consecutive gastric or gastroesophageal junction adenocarcinoma patients in stages T3–4/N+ were treated with postoperative radiotherapy and chemotherapy. The recommended treatment plan was radical resection followed by 1–2 cycles of adjuvant chemotherapy (ACT), postoperative chemoradiotherapy (CRT), and, finally, 4–5 cycles of ACT. The patients were classified into two groups depending on the number of cycles of ACT: group 1 received 4–6 cycles (n = 59), and group 2 received 0–3 cycles (n = 38). The detailed grouping is as follows: RT alone, 2; RT and CT, 18; concurrent RTCT and CT, 41; and CRT, 36. Of the 97 patients, 77 patients received concurrent therapy (CRT, (5-fluorouracil or capecitabine), and 20 received radiotherapy alone because of patient refusal (n = 15) or treatment toxicity (n = 5). After a median follow-up of 44 months, the 3-year disease free survival(DFS) and overall survival (OS) were 66.5% and 69.5% for group 1 and 45.5% and 50% for group 2, respectively (p = 0.005 and p = 0.024). Multivariate analysis revealed that 4–6 cycles of ACT, lymphovascular invasion, or peritoneal metastasis were independent prognostic factors for disease-free survival or overall survival (p<0.05). Conclusions/Significance This study demonstrates that concurrent chemoradiation with adjuvant epirubicin-based triplet chemotherapy is feasible and tolerable for gastric or gastroesophageal junction carcinoma patients. Patients can benefit from more cycles of ACT.

TNF rs1799964 as a Predictive Factor of Acute Toxicities in Chinese Rectal Cancer Patients Treated With Chemoradiotherapy

AbstractAcute toxicity is the main dose-limiting factor in the chemoradiotherapy of rectal cancer patients and depends on several pro-inflammatory factors, including interleukin-1 (IL-1), IL-6, and tumor necrosis factor-alpha (TNF-&agr;). It is unknown whether genetic factors, such as single-nucleotide polymorphisms (SNPs) in the IL-1, IL-6, and TNF genes, are also associated with acute toxicity in the process.We genotyped 5 potentially functional SNPs in these 3 genes (TNF rs1799964, TNF rs1800629, IL-6 rs1800796, and IL-1 rs1143623, IL-1 rs1143627) and estimated their associations with severe acute radiation injury (grade ≥2) in 356 rectal cancer patients.We found a predictive role of the TNF rs1799964 T variant allele in the development of acute injury (for CT vs CC: adjusted odds ratio [OR] = 4.718, 95% confidence interval [CI] = 1.152–19.328, P = 0.031; for TT vs CC: adjusted OR = 4.443, 95% CI = 1.123–17.581, P = 0.034). In the dominant model, for CT/TT vs CC, the adjusted OR = 4.132, 95% CI = 1.069–15.966, and P = 0.04.Our results suggested that genetic variants in the TNF gene may influence acute injury in rectal cancer patients treated with chemoradiotherapy and may be a predictor for personalized treatment. Additional larger and independent studies are needed to confirm our findings.

Phase II trial of preoperative chemoradiation plus perioperative SOX chemotherapy in patients with locally advanced gastric cancer

The ideal treatment strategy of patients with locally advanced gastric adenocarcinoma is unclear. The aim of this study is to evaluate the efficacy and feasibility of preoperative chemoradiation in these patients.

Identification of patients with lymph node metastasis from gastric cancer who may benefit from adjuvant chemoradiotherapy after D2 dissection—do N3 patients benefit from additional radiation?

OBJECTIVE The role of adjuvant chemoradiotherapy (CRT) in locally advanced gastric cancer (LAGC) after D2 dissection is controversial. Subgroup analysis of the ARTIST trial indicated that patients with lymph node metastasis might benefit from additional radiation. The present study compared adjuvant CRT with adjuvant chemotherapy (CT) for the treatment of lymph node metastasis and suggested patient-selection guidelines. METHODS Patients with LAGC and positive lymph nodes who underwent D2, R0 gastrectomy in our hospital were retrospectively investigated. Patients were divided into two balanced groups by the use of propensity-score matching: CRT group (n = 138) received adjuvant CRT with fluorouracil-based regimens and radiation (45-50.4 Gy), and the CT group (n = 138) received adjuvant CT alone. RESULTS Of the 276 patients, 147 patients died (69 patients in the CRT group and 78 patients in the CT group), and 151 patients experienced recurrence (65 patients in the CRT group and 86 patients in the CT group). The estimated 3-year disease-free survival (DFS) and overall survival in the CRT and CT groups were 51.5% vs 41.3% (p = 0.05) and 52.0% vs 50.1% (p = 0.35), respectively. The risk of local regional recurrence was increased in the CT group compared with the CRT group (16.7% vs 8.7%, p = 0.04, respectively). In the subgroup analysis, patients with N1-2 stage were associated with better survival from CRT (hazard ratio = 0.44, p = 0.01). CONCLUSION Adjuvant CRT may improve the 3-year DFS and local control in patients with LAGC after D2 dissection. Investigation of stratification factors for patient selection is warranted. ADVANCES IN KNOWLEDGE Patients with N1-2 stage rather than those with N3 stage benefit most from additional radiation after D2 dissection.