Plasmodium circumsporozoite protein suppresses the growth of A549 cells via inhibiting nuclear transcription factor κB.

Blocking the activation of nuclear factor κB (NF-κB) is a promising strategy for the treatment of non-small cell lung cancer. The circumsporozoite protein (CSP), a key component of the sporozoite stage of the malaria parasite, was previously reported to block NF-κB activation in hepatocytes. Therefore, in the present study, the effect of CSP on the growth of the human lung cancer cell line, A549, was investigated. It was demonstrated that transfection with a recombinant plasmid expressing CSP was able to inhibit the proliferation of A549 cells in a dose-dependent manner and induce the apoptosis of A549 cells. A NF-κB gene reporter assay indicated that CSP and its nuclear localization signal (NLS) motif were able to equally suppress the activation of NF-κB following stimulation with human recombinant tumor necrosis factor (TNF)-α in A549 cells. Furthermore, western blot analysis indicated that NLS did not affect the phosphorylation and degradation of IκB, but was able to markedly inhibit the nuclear translocation of NF-κB in TNF-α stimulated A549 cells. Therefore, the data suggest that CSP may be investigated as a potential novel NF-κB inhibitor for the treatment of lung cancer.

Single chest tube drainage is superior to double chest tube drainage after lobectomy: a meta-analysis.

BACKGROUND: In this meta-analysis, we conducted a pooled analysis of clinical studies comparing the efficacy of single chest tube versus double chest tube after a lobectomy. METHODS: According to the recommendations of the Cochrane Collaboration, we established a rigorous study protocol. We performed a systematic electronic search of the PubMed, Embase, Cochrane Library and Web of Science databases to identify articles to include in our meta-analysis. A literature search was performed using relevant keywords. A meta-analysis was performed using RevMan© software. RESULTS: Five studies, published between 2003 and 2014, including 630 patients (314 patients with a single chest tube and 316 patients with a double chest tube), met the selection criteria. From the available data, the patients using a single tube demonstrated significantly decreased postoperative pain [weighted mean difference [WMD] -0.60; 95 % confidence intervals [CIs] -0.68-- 0.52; P < 0.00001], duration of drainage [WMD -0.70; 95 % CIs -0.90-- 0.49; P < 0.00001] and hospital stay [WMD -0.51; 95 % CIs -0.91-- 0.12; P = 0.01] compared to patients using a double tube after a pulmonary lobectomy. However, there were no significant differences in postoperative complications [OR 0.91; 95 % CIs 0.57-1.44; P = 0.67] and re-drainage rates [OR 0.81; 95 % CIs 0.42-1.58; P = 0.54]. CONCLUSION: Our results showed that a single-drain method is effective, reducing postoperative pain, hospitalization times and duration of drainage in patients who undergo a lobectomy. Moreover, the single-drain method does not increase the occurrence of postoperative complications and re-drainage rates.

Lymph node micrometastases are associated with disease recurrence and poor survival for early-stage non-small cell lung cancer patients: a meta-analysis.

BACKGROUND: We performed a meta-analysis to clarify whether the molecular detection of tumor cells or micrometastases in the lymph node (LN) indicates a high risk of disease recurrence and poor survival in negative pathologic lymph node status non-small cell lung cancer (NSCLC). METHODS: A literature search was performed using relevant keywords. We searched relevant studies from PubMed, Embase, and the Cochrane Library. Direct and indirect meta-estimates were generated using Review Manager software with fixed effects for the study. Study-to-study heterogeneity was summarized using I (2) statistics and predictive intervals (PIs). RESULTS: Our analysis of eight eligible studies revealed that patients with lymph node micrometastases (LNMM) were associated with poor overall survival (OS) (HR, 1.98; 95 % CI, 1.50 to 2.62; p < 0.00001) and disease-free survival (DFS) (HR, 2.34; 95 % CI, 1.67-3.27; p < 0.00001). CONCLUSION: LNMM is associated with an increased risk of disease recurrence and poor survival in patients with negative pathologic node negative NSCLC. Thus, these patients need to be carefully followed up after the initial pulmonary resection.

The Effectiveness of Postoperative Radiotherapy in Patients With Completely Resected Thymoma: A Meta-Analysis.

BACKGROUND: This meta-analysis aimed to provide a pooled analysis of clinical studies correlating postoperative radiotherapy (PORT) with survival in patients with completely resected thymoma. METHODS: According to the recommendations of the Cochrane Collaboration, we established a rigorous study protocol. An electronic search was conducted using online databases. Hazard ratios (HRs) and 95% confidence intervals (CIs) were used in this meta-analysis and were calculated from published survival data. A meta-analysis was conducted to assess the impact of PORT in completely resected thymoma on overall survival (OS), disease-free survival (DFS). and disease-specific survival (DSS). We also performed a subgroup analysis for OS of patients with stage II and stage III thymoma. RESULTS: Fourteen studies, which included 3,823 patients (2,096 patients who received PORT and 1,727 patients who did not receive PORT), met the selection criteria. From the available data, the thymoma patients with PORT who did not undergo resection did not have significantly improved OS (HR 0.99; 95% CI 0.87 to 1.13; p = 0.87), DFS (HR 1.21; 95% CI 0.97 to 1.51; p = 0.09), or DSS (HR 0.66; 95% CI 0.39 to 1.13; p = 0.13) compared with the patients who did not undergo PORT. However, our subgroup analysis showed a significant difference in OS in patients with stage II thymoma (HR 0.57; 95% CI 0.41 to 0.80; p = 0.001) and patients with stage III thymoma (HR 0.73; 95% CI 0.59 to 0.90; p = 0.004). CONCLUSION: Our results showed that for completely resected thymoma, PORT had no advantage in the overall group of patients but increased OS in the patients with stage II and III thymoma after a complete resection. On the basis of this study, PORT is beneficial in patients with stage II and III patients after a complete resection.

Comparison of two different mechanical esophagogastric anastomosis in esophageal cancer patients: a meta-analysis.

OBJECTIVE: In this meta-analysis, we conducted a pooled analysis of clinical studies comparing Linear Stapled (LS) versus Circular Stapled (CS) esophagogastric anastomosis for esophageal cancer. METHODS: According to the recommendations of the Cochrane Collaboration, we established a rigorous study protocol. We performed a systematic electronic search of the PubMed, Embase, Cochrane Library, Web of Science, and Chinese Biomedical databases as well as Chinese scientific journals to identify articles to include in our meta-analysis. The primary outcomes compared were anastomotic leak, anastomotic stricture and 3-month mortality. RESULTS: Five controlled trials comprising 840 patients (523 LS vs. 317 CS) were included. Primary outcomes revealed a statistically significant decrease in anastomotic strictures [risk ratio (RR): 0.26, 95 % confidence interval (CI): 0.11-0.60, P = 0.002] compared with linear stapled anastomosis. However, there were no significant differences between the two groups with respect to anastomotic leakage [risk ratio (RR): 0.80, 95 % confidence interval (CI): 0.40-1.58, P = 0.52] and 3-month mortality [risk ratio (RR): 0.94, 95 % confidence interval (CI): 0.47-1.87, P = 0.85]. CONCLUSION: There were no statistical differences in the rate of 3-month mortality or anastomotic leakage between the two groups. However, the LS method contributed to a reduced rate of anastomotic strictures. This meta-analysis may offer some specific suggestions for esophagogastric anastomosis.

Hand-sewn vs linearly stapled esophagogastric anastomosis for esophageal cancer: a meta-analysis.

AIM: To compare the outcomes of hand-sewn (HS) and linearly stapled (LS) esophagogastric anastomosis for esophageal cancer. METHODS: Before beginning this study, a rigorous protocol was established according to the recommendations of the Cochrane Collaboration. Databases and references were searched for all randomized controlled trials and comparative clinical studies that compared LS with HS esophagogastric anastomosis for esophageal cancer. The primary outcomes compared were anastomotic leak and stricture. Subgroup analyses were performed according to site of anastomosis. RESULTS: Fifteen studies were used, comprising 3203 patients (n = 2027 LS and 1176 HS). Primary outcome analysis revealed a significant decrease in anastomotic leakage (RR = 0.51, 95%CI: 0.41-0.65; P < 0.00001) associated with LS anastomosis. A significantly reduced rate of anastomotic stricture associated with LS was also found (RR = 0.56, 95%CI: 0.49-0.64; P < 0.00001). A subgroup analysis according to the site of anastomosis revealed a significantly reduced rate of anastomotic stricture (P < 0.00001). Although there was no significant difference in the decrease in thoracic anastomotic leakage, there was a significant decrease in cervical anastomotic leakage associated with LS (P < 0.00001). CONCLUSION: This meta-analysis indicates that the LS technique contributes to a reduced rate of leakage and stricture compared with the HS method.

Bone marrow micrometastasis is associated with both disease recurrence and poor survival in surgical patients with node-negative non-small-cell lung cancer: a meta-analysis.

OBJECTIVES: We performed a meta-analysis in order to determine whether the molecular tumour cell detection of either micrometastasis or isolated tumour cells in the bone marrow micrometastasis is indicative of a high risk of both disease recurrence and poor survival in the setting of node-negative non-small-cell lung cancer (NSCLC). METHODS: Before beginning this study, a rigorous protocol was established in accordance with the recommendations of the Cochrane Collaboration. A systematic literature search of Medline, EMbase, the Cochrane Library and the Web of Science was conducted in order to identify studies regarding the prognostic value of molecular tumour cell detection in the bone marrow of node-negative NSCLC. Any study describing the use of both immunochemistry and flow cytometry to detect bone marrow metastasis was selected. We extracted the associated 95% confidence intervals (CIs) and hazard ratios (HRs) from the included studies and performed meta-analyses on overall survival and either disease-free survival (DFS) or disease-free recurrence. Meanwhile, we compared the occurrence of bone marrow micrometastasis among different pathological types and different stages of disease. RESULTS: Eleven studies with a cumulative sample size of 2159 patients were included in our analysis. Our meta-analyses revealed that the occurrence of bone marrow micrometastasis was not related to patient pathological types and stages in cancers ranging from adenocarcinoma and squamous cell carcinoma [relative risk (RR): 0.92; 95% CI: 0.78-1.08; P = 0.29], stages I and II (RR: 0.88; 95% CI: 0.67-1.17; P = 0. 39), stages II and III (RR: 0.98; 95% CI: 0.73-1.31; P = 0.89) and stages I and III (RR: 0.84; 95% CI: 0.68-1.05; P = 0.13). However, molecular tumour cell detection within the bone marrow was associated with both poor OS (HR: 1.84; 95% CI: 1.41-2.40; P < 0.00001) and poor DFS (HR: 1.75; 95% CI: 1.18-2.60; P = 0.005). Our subgroup analyses indicated that the presence of bone marrow micrometastasis was not a significant prognostic factor with respect to DFS at stage I (HR: 2.35; 95% CI: 0.67-8.25; P = 0.18). CONCLUSIONS: The molecular detection of isolated tumour cell in the bone marrow is associated with both poor survival and an increased rate of recurrence in patients with node-negative NSCLC; this approach may result in the development of a new metastatic cascade concept and the development of novel approaches to cancer therapy.

Esophageal Cancer with a Synchronous Multiple Carcinoid of the Duodenal Bulb.

Carcinoid tumors of the duodenum are relatively rare. Although they were considered benign lesions, they are now classified malignant, occasionally with poor prognosis. We report a case of esophageal cancer with a synchronous multiple carcinoid of the duodenal bulb. An upper endoscopy visualized with esophageal scan disclosed a stenotic lesion in the lower esophagus and revealed multiple 4--5-mm-diameter masses which were on the fore wall of the duodenal bulb. The postoperative pathology report confirmed the diagnosis of esophageal squamous cancer and duodenal bulb carcinoid.

Comparison of outcomes following end-to-end hand-sewn and mechanical oesophagogastric anastomosis after oesophagectomy for carcinoma: a prospective randomized controlled trial.

OBJECTIVES: The effects of the use of the stapler or hand-sewn method in oesophagogastric anastomosis on postoperative morbidity, mortality and quality of life after oesophagectomy remain controversial. The purpose of his study was to compare clinical outcomes of hand-sewn and stapler techniques in oesophagogastric anastomosis after oesophagectomy for oesophageal carcinoma. METHODS: We performed a prospective randomized controlled trial on 478 patients treated for oesophageal tumour between February 2009 and December 2011. Patients were randomly assigned to two treatment groups with 237 patients in the hand-sewn group and 241 patients in the circular stapler group (http://www.chictr.org: ChiCTR-TRC-13004428). RESULTS: The mean follow-up time was 18 months. The mean operating time of the stapled group and the hand-sewn group were 193 and 226 min, respectively (P < 0.001). Seventeen clinical and radiological leakages occurred in the hand-sewn group compared with 7 in the stapler group (P = 0.033). In the stapler group hospital mortality occurred in 10 patients (4.3%) and in the hand-sewn group in 9 patients (3.9%) (P = 0.837). Anastomotic strictures were noted in 31 patients from the stapler group (14.2%) and in 16 patients from the hand-sewn group (7.5%) (P = 0.027). CONCLUSIONS: Using the circular stapler method in oesophagogastric anastomoses had a lower anastomotic leakage rate and shorter operating time compared with the hand-sewn method. However, the circular stapler method was associated with a significantly increased risk of anastomotic strictures.

Oesophageal flap valvuloplasty and wrapping suturing prevent gastrooesophageal reflux disease in dogs after oesophageal anastomosis.

AIM: To examine the efficiency of oesophageal flap valvuloplasty and wrapping suturing technique in decreasing the rate of postoperative gastrooesophageal reflux disease in a dog model. METHODS: We operated on 10 dogs in this study. First, we resected a 5-cm portion of the distal oesophagus and then restored the continuity of the oesophageal and gastric walls by end-to-end anastomosis. A group of five dogs was subjected to the oesophageal flap valvuloplasty and wrapping suturing technique, whereas another group (control) of five dogs was subjected to the stapling technique after oesophagectomy. The symptom of gastrooesophageal reflux was recorded by 24-h pH oesophageal monitoring. Endoscopy and barium swallow examination were performed on all dogs. Anastomotic leakage was observed by X-ray imaging, whereas benign anastomotic stricture and mucosal damage were observed by endoscopy. RESULTS: None of the 10 dogs experienced anastomotic leakage after oesophagectomy. Four dogs in the new technology group resumed regular feeding, whereas only two of the dogs in the control group tolerated solid food intake. pH monitoring demonstrated that 25% of the dogs in the experimental group exhibited reflux and that none had mucosal damage consistent with reflux. Conversely, both reflux and mucosal damage were observed in all dogs in the control group. CONCLUSION: The oesophageal flap valvuloplasty and wrapping suturing technique can improve the postoperative quality of life through the long-term elimination of reflux oesophagitis and decreased stricture formation after primary oesophageal anastomosis.

Preventing and localizing esophagogastric anastomosis leakage by sleeve-wrapping of the pedicled omentum.

AIM: To develop a technique of sleeve-wrapping the pedicled omentum around the esophagogastric anastomosis for preventing and localizing leakage. METHODS: This study includes data from 86 patients who were diagnosed with esophageal cancer and underwent the technique of sleeve-wrapping the pedicled omentum around esophagogastric anastomosis after esophagectomy between November 2011 and July 2013. The early complications that occurred during follow-up were analyzed. RESULTS: Postoperative complications included pulmonary complications (13/86; 15.1%) and abdominal or thoracic wound infection (3/86; 3.5%). Complications that occurred during follow-up included one case of anastomosis leakage (limited by omentum; 1.2%) and five case of anastomosis stricture (5.8%). No deaths occurred. All complications were resolved through traditional treatment. No additional surgery was needed. CONCLUSION: Sleeve-wrapping of the pedicled omentum around esophagogastric anastomosis after esophagectomy is safe and effective for preventing and localizing anastomosis leakage without increasing anastomosis stricture.

Is hand sewing comparable with stapling for anastomotic leakage after esophagectomy? A meta-analysis.

AIM: To compare the outcome of hand sewing and stapling for anastomotic leakage after esophagectomy. METHODS: A rigorous study protocol was established according to the recommendations of the Cochrane Collaboration. An electronic database search, hand search, and reference search were used to retrieve all randomized controlled trials that compared hand-sewn and mechanical esophagogastric anastomoses. RESULTS: This study included 15 randomized controlled trials with a total of 2337 patients. The results revealed that there was no significant difference in the incidence of anastomotic leakage between the methods [relative risk (RR) = 0.77, 95% confidence interval (CI): 0.57-1.04; P = 0.09], but a subgroup analysis yielded a significant difference for the sutured layer and year of publication (Ps < 0.05). There was also no significant difference in the incidence of postoperative mortality (RR = 1.52, 95%CI: 0.97-2.40; P = 0.07). However, the anastomotic strictures rate was increased in the stapler group compared with the hand-sewn group (RR = 1.45, 95%CI: 1.11-1.91; P < 0.01) in the end-to-side subgroup, while the incidence of anastomotic strictures was decreased (RR = 0.34, 95%CI: 0.16-0.76; P < 0.01) in the side-to-side subgroup. CONCLUSION: The stapler reduces the anastomotic leakage rate compared with hand sewing. End-to-side stapling increases the risk of anastomotic strictures, but side-to-side stapling decreases the risk.

Mitochondrial genome microsatellite instability and copy number alteration in lung carcinomas.

OBJECTIVE: Mitochondrial DNA (mtDNA) is considered a hotspot of mutations in various tumors. However, the relationship between microsatellite instability (MSI) and mtDNA copy number alterations in lung cancer has yet to be fully clarifieds. In the current study, we investigated the copy number and MSI of mitochondrial genome in lung carcinomas, as well as their significance for cancer development. METHODS: The copy number and MSI of mtDNA in 37 matched lung carcinoma/adjacent histological normal lung tissue samples were examined by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) assays for sequence variation, followed by sequence analysis and fluorogenic 5'-nuclease real-time PCR. Student's t test and linear regression analyses were employed to analyze the association between mtDNA copy number alterations and mitochondrial MSI (mtMSI). RESULTS: The mean copy number of mtDNA in lung carcinoma tissue samples was significantly lower than that of the adjacent histologically normal lung tissue samples (p < 0.001). mtMSI was detected in 32.4% (12/37) of lung carcinoma samples. The average copy number of mtDNA in lung carcinoma samples containing mtMSI was significantly lower than that in the other lung carcinoma samples (P < 0.05). CONCLUSIONS: Results suggest that mtMSI may be an early and important event in the progression of lung carcinogenesis, particularly in association with variation in mtDNA copy number.

Wrapping of the omental pedicle flap around esophagogastric anastomosis after esophagectomy for esophageal cancer.

BACKGROUND: Esophagogastrectomy for esophageal cancer is the standard surgical treatment as a curative measure or for palliation. Esophagogastric anastomotic leakage and stricture are common life-threatening postoperative complications (more so if the leakage occurs in the chest), and the success of the anastomosis created in the reconstruction of the resected esophagus can highly influence morbidity and mortality. METHODS: A prospective, randomized study was undertaken on 291 patients treated for carcinoma of the esophagus between January 2004 and December 2008. The study excluded 36 patients (12%) who were inoperable. Patients were assigned to 2 treatment groups that consisted of 128 patients in group A and 127 patients in group B according to a restricted, permuted block randomization plan. Patients in group A underwent an esophagogastrectomy with wrapping of the pedicle omental flap around the esophagogastric anastomosis. Group B patients underwent an esophagogastrectomy with only a stapled technique. RESULTS: Of all 255 patients who received an esophagogastric anastomosis, 226 (89%) were discharged from the hospital within 15 days of operation. There was no significant difference between these 2 groups in regard to the incidence of pulmonary complications, abdominal or thoracic infections, and days of hospital stay. Anastomotic leaks occurred in a single patient from group A (1%) and in 7 patients from group B (6%). In group A, 33 patients underwent transhiatal esophagogastrectomy and 95 had thoracic esophagogastrectomy, which resulted in an anastomotic leakage in 1 (3%) and 0 (0%) patients, respectively. In group B, 42 patients had transhiatal esophagogastrectomy and 85 had thoracic esophagogastrectomy, which resulted in anastomotic leakage in 5 (12%) and 2 (2%) patients, respectively. The leakage ratio of group B was significant greater than that of group A (P < .05). Two patients were excluded during the evaluation of the benign stricture due to hospital mortality. Anastomotic strictures were noted in 8 patients from group A (6%) and 20 patients from group B (16%), and the difference in the incidence of anastomotic strictures between these 2 groups was statistically significant (P < .05). CONCLUSION: Wrapping of the pedicle omental flap around the esophagogastric stapled anastomosis site decreases the incidence of anastomotic leakage and stricture rate after esophagectomy for esophageal cancer, thereby decreasing the morbidity and mortality of the procedure.

Restoration of SOCS3 suppresses human lung adenocarcinoma cell growth by downregulating activation of Erk1/2, Akt apart from STAT3.

SOCS3 is regarded as a major negative regulator of STAT3. Recent evidence indicates that SOCS3 regulates strength and duration of other signaling pathways including ras/ERK1/2/MAPK, PI3-K/Akt in non-malignant cells. The repression or silence of SOCS3 expression in a few tumor types has led to speculation that loss of SOCS3 gene is closely related to deregulation of multiple signal pathways during tumorigenesis. However, apart from STAT3, little is known in malignant cells about the mechanism by which SOCS3 modulates other intracellular signal cascades such as Erk1/2 and Akt, whose aberrant activation has been implicated in many human tumors. Expression of SOCS3 proved deficient in human lung adenocarcinoma A549 cells, and forced expression of SOCS3 resulted in growth inhibition. Growth suppression due to SOCS3 was associated with attenuated activation of Erk1/2, Akt as well as STAT3. The results suggested that SOCS3, as negative regulators of cytokine signaling, might maintain homeostasis by regulating multiple signaling pathways and reverse cell malignant behavior.

Mitochondrial DNA 4977 BP deletion mutations in lung carcinoma.

BACKGROUND: The most common and also the most often assayed mtDNA deletion mutation, degrees mtDNA 4,977 sub has been demonstrated in various types of human cancer. However, knowledge about degrees mtDNA 4,977 in lung carcinoma is poor. AIM: To study the 4,977 bp deletions of mitochondrial DNA ( degrees mtDNA 4,977) in lung cancer, adjacent histologically normal and normal lung tissue and its potential roles in the development of cancer. MATERIALS AND METHODS: Thirty-seven matched lung cancer/adjacent histologically normal and 20 histologically normal lung tissue samples in subjects without lung cancer were analyzed by PCR technique. RESULTS: degrees mtDNA 4,977 deletions were detected in 54.1% (20/37) of lung cancers, 59.5% (22/37) of adjacent normal and 30.0% (6/20) of normal lung tissue samples. No significant difference was found in the frequency of degrees mtDNA 4,977 deletions between the tumor and adjacent normal lung tissues (P value = 0.815). Moreover, no significant difference was found in the frequency of degrees mtDNA 4,977 deletions between the tumor and histologically normal lung tissues in subjects without lung cancer (P value=0.101). However, the correlation between degrees mtDNA 4,977 deletion and age and smoking factors was present in our data. STATISTICAL ANALYSIS: Fisher's exact test was used to assess the difference in different groups by the Scientific Package for Social Sciences (SPSS), version 10.0, Statistical analysis software. CONCLUSIONS: Mitochondrial DNA 4,977 bp deletion, which is not specific to lung cancer, may reflect the environmental and aging process influences operative during tumor progression.

The absence of mitochondrial DNA diversity among common laboratory inbred mouse strains.

Mitochondrial DNA (mtDNA), which exhibits a maternal inheritance and a high rate of evolution, has been widely used as a genetic marker when analyzing maternal lineage and inferring phylogenetic relationships among species. In this study, mtDNA variations among four classical (BALB/c, C3H, C57BL/6J and DBA/2) and three Chinese (TA2, 615 and T739) inbred strains of laboratory mice were analyzed by PCR-RFLP (polymerase chain reaction coupled with restriction fragment length polymorphism) and PCR-SSCP (polymerase chain reaction coupled with single-stranded conformational polymorphism) techniques. PCR-RFLP analyses on 46 restriction sites revealed no variations in mtDNA D-loop (displacement loop), tRNA(Met+Glu+Ile) and ND3 (NADH dehydrogenase subunit 3) gene fragments in these strains. Furthermore, PCR-SSCP analyses demonstrated no variations in D-loop 5' and 3' end fragments in them. In view of enormous polymorphisms in mtDNA among mice and dramatic differences in nuclear genomes of these seven strains, our findings were surprising. However, in light of the maternal inheritance of mtDNA, the results indicate that the three Chinese strains, including TA2, T739 and 615, and the four classical strains, share a common maternal lineage.

Mitochondrial DNA sequence analysis of two mouse hepatocarcinoma cell lines.

AIM: To study genetic difference of mitochondrial DNA (mtDNA) between two hepatocarcinoma cell lines (Hca-F and Hca-P) with diverse metastatic characteristics and the relationship between mtDNA changes in cancer cells and their oncogenic phenotype. METHODS: Mitochondrial DNA D-loop, tRNA(Met+Glu+Ile) and ND3 gene fragments from the hepatocarcinoma cell lines with 1 100, 1 126 and 534 bp in length respectively were analysed by PCR amplification and restriction fragment length polymorphism techniques. The D-loop 3' end sequence of the hepatocarcinoma cell lines was determined by sequencing. RESULTS: No amplification fragment length polymorphism and restriction fragment length polymorphism were observed in tRNA(Met+Glu+Ile), ND3 and D-loop of mitochondrial DNA of the hepatocarcinoma cells. Sequence differences between Hca-F and Hca-P were found in mtDNA D-loop. CONCLUSION: Deletion mutations of mitochondrial DNA restriction fragment may not play a significant role in carcinogenesis. Genetic difference of mtDNA D-loop between Hca-F and Hca-P, which may reflect the environmental and genetic influences during tumor progression, could be linked to their tumorigenic phenotypes.

[mtDNA mutations in mouse tumors].

OBJECTIVE: To investigate variations of mtDNA in mouse tumors and to explore the relationship between mtDNA mutations and murine carcinogenesis. METHODS: Variations of D-loop, ND3 and tRNAIle + Glu + Met gene fragments of mtDNA from six mouse tumor cell lines were analyzed by PCR-RFLP and PCR-SSCP techniques. RESULTS: ND3 and tRNAIle + Glu + Met gene fragments of mtDNA from the tumors showed no variations at 27 endonuclease sites. The D-loop of mtDNA from Hca-F demonstrated an additional endonuclease site of Hinf I in contrast to the inbred mouse. Upon PCR-SSCP analysis, the D-loop of mtDNA was found to possess mutations in 4 of 6 tumors. CONCLUSION: D-loop appears to be the hot spot for tumor mtDNA mutations, which may contribute to the carcinogenesis of murine tumors.