A nitinol "U-Clip" versus sutured arteriovenous anastomosis: local tissue response and intimal hyperplasia development in a sheep model.

OBJECTIVES: This study sought to compare the local tissue response and subsequent volume of intimal hyperplasia (IH) that develops throughout the maturation of an arteriovenous fistula created using continuous/interrupted polypropylene with that of a novel, metal-alloy, penetrating anastomotic clip device. MATERIALS AND METHODS: Forty-six fistulae were created in 23 sheep under a paired design using the nitinol U-Clip (n = 23) in one hind limb and continuous (n = 20) or interrupted (n = 3) polypropylene suture for the other. Animals were killed at 4 (n = 3), 14 (n = 3), 28 (n = 10), 42 (n = 3), and 180 (n = 4) days. Histological sections were evaluated for quantitative histology and immunohistochemistry. RESULTS: Compared with continuous polypropylene, U-Clip specimens demonstrated less intima-media area per unit length (IMA/L), proliferating cells, and tissue necrosis at all time points (MANOVA, F = 9.8-24.1, all p ≤ .005; observed power >82%). Specifically, values of IMA/L were reduced by 5% (p = .97), 37% (p = .02), 33% (p < .01), 9% (p = .42), and 14% (p = .22) at the time points of 4, 14, 28, 42, and 180 days respectively. Proliferating cells were reduced by 75% (p < .01), 72% (p = .03), 76% (p = .03), 27% (p = .31), and 60% (p = .01) and tissue necrosis by 67% (p < .01), 58% (p = .02), 40% (p = .33), 21% (p = .43), 77% (p = .11). In a 28-day comparison between U-Clip and interrupted polypropylene the U-Clip group demonstrated a 4% (p = .65) reduction in IMA/L, 74% (p < .01) in proliferating cells and 49% (p < .05) in tissue necrosis. CONCLUSIONS: These results provide evidence of reduced local tissue necrosis, proliferating cells, and IH, favouring arteriovenous fistulae created using the U-Clip anastomotic device over conventional polypropylene suture techniques most evident over the first 4 weeks.

An arteriovenous fistula model of intimal hyperplasia for evaluation of a nitinol U-Clip anastomosis.

OBJECTIVES: The aim of this study was to create an ovine arteriovenous fistula (AVF) model which would closely replicate a human forearm fistula and use this to quantify the degree of intimal hyperplasia in those created with the U-Clip compared to a conventional sutured anastomosis. MATERIALS AND METHODS: Twenty AVFs were created in 10 Border Leicester-Merino sheep between the superficial femoral artery and vein of each hind limb. On one side the U-Clip and on the other a continuous polypropylene suture was used to perform the anastomosis. The animals were sacrificed at 2 (n = 3), 4 (n = 4), 6 (n = 3) weeks and histological slices were taken of each AVF in cross section to determine the intimal media area per unit length (IMA/L). RESULTS: Intimal hyperplasia (IH) was observed at all time points with one AVF found occluded with thrombus at the time of harvest. The IMA/L was significantly lower in the U-Clip groups by 24% at 2 weeks, 32% at 4 weeks and 23% at 6 weeks (Two-way ANOVA, p = 0.019, observed power = 0.825, time or side p ≥ 0.766, type p = 0.001; Paired t-test, p < 0.001 between matched anastomotic types). Time taken to perform the anastomosis was similar between the two anastomotic techniques (Polypropylene 14(8-18) vs. U-Clip 15.3(11-23) min; p = 0.47). CONCLUSION: This ovine AVF model results in IH similar to that seen in a human AVF. The IH that occurs with the U-Clip is less than that of continuous polypropylene suture.

P53 expression is associated with malignant potential in xenograft tissues of a fibrosarcoma mouse model.

BACKGROUND: The expression of wild-type and mutant p53 was studied in two fibrosarcoma cell lines in a mouse xenograft model. MATERIALS AND METHODS: Human cell lines HT1080 and Hs913(D)T were implanted in athymic mice via intramuscular (i.m.) or subcutaneous (s.c.) routes. After eight weeks, liver, lung and primary inoculation sites were harvested. Sections were stained using two methods: a) haematoxylin and eosin to detect tumour at implantation site, liver and lung; b) immunohistochemistry using monoclonal antibodies to detect expression of wild-type (wt) and mutant p53. RESULTS: Both cell lines had similar implantation rates via either route but Hs913(D)T had a higher metastatic rate than HT1080. The Hs913(D)T cells exhibited greater expression of mutant and wild-type p53 than the HT1080 cells. CONCLUSION: The expression of wild-type and mutant p53 is associated with a cell line of greater malignant potential. The inoculation route does not affect primary tumour uptake or metastatic rate.

Expression of HER1/EGFR protein in human soft tissue sarcomas.

AIM: To measure epidermal growth factor receptor (HER1/EGFR) expression in a range of soft tissue sarcoma (STS) patient samples. METHOD: HER1/EGFR expression was examined by immunohistochemistry in archival tissues of 46 STS patients. RESULTS: HER1/EGFR was positively expressed in 36/46 of STS samples distributed among different histological types. The levels of HER1/EGFR in STS tumour tissues in positive samples were higher compared to those in nearby normal tissues. CONCLUSION: HER1/EGFR is significantly expressed in soft tissue sarcomas, which is a finding reflected in other series. The significance of this finding for targeted therapy is as yet unknown.

Genetic markers of survival and liver recurrence after resection of liver metastases from colorectal cancer.

A significant number of patients with liver metastases from colorectal cancer (CRC) achieve 5-year survival after liver resection. Increased expression of genetic markers in the primary tumor are known to predict outcome after colonic resection, but the predictive value of such markers after resection of hepatic metastases is unknown. The objective of this study was to evaluate whether DNA content and multiple genetic markers, separately or expressed together, can predict patient outcome (liver recurrence and survival) after resection of hepatic metastases. We studied the paraffin-embedded liver tissue of 71 consecutive patients who had undergone a potentially curative resection of hepatic metastases from CRC. Using DNA flow cytometry and immunohistochemical staining techniques we determined the DNA content and the level of co-expression of seven tumor-associated proteins: proliferating cellular nuclear antigen (PCNA), epidermal growth factor receptor (EGFr), p53, c-erbB-2, H-ras, c-myc, and nm23. Three endpoints (liver recurrence, cancer specific, overall survival) were correlated with these tumor markers. The 5-year overall survival of the group was 31.2%. There was no correlation detected between the DNA aneuploidy and overall or cancer-specific survival. Similarly, expression of the individual tumor-associated proteins did not predict survival. Patients whose tumors co-expressed multiple markers had survivals similar to those whose tumors expressed fewer markers. However, a significant difference in hepatic recurrence was found between the p53-positive and p53-negative patients (p = 0.007), with marker-negative tumors having decreased recurrence. In conclusion, this study demonstrates that the DNA content and genetic markers c-myc, c-erbB-2, EGFr, H-ras, p53, PCNA, and nm23 do not predict survival after potentially curative resection of hepatic metastases from CRC. However, the immunoreactivity of p53 may be an important marker of local recurrence in the liver, which may be useful if re-resection of metastatic liver tumors is considered a viable management option in this disease.

Urokinase-type plasminogen activator and its receptor in colorectal cancer: independent prognostic factors of metastasis and cancer-specific survival and potential therapeutic targets.

Urokinase-type plasminogen activator (uPA) and its receptor (uPAR), plasminogen (Plg), and plasminogen activator inhibitors-1 and -2 (PAI-1 and PAI-2) have been observed in many cancers and may contribute to progression and metastasis. In our study, we examined the expression of the 5 proteins by immunohistochemistry in 59 consecutive primary colorectal cancers (CRC) and correlated the protein expression with patient outcome. In addition, we determined the effect of down-regulation of uPAR on the invasive/metastatic capability of CRC cells, by measuring antisense-uPAR transfected HCT116 and control cell lines, in terms of uPAR expression, uPA-binding activity, invasiveness through Matrigel in vitro and metastasis after cecal orthotopic implantation in nude mice in vivo. We found that higher expression of uPA or uPAR in primary tumor tissues was positively correlated with distant metastasis of CRC (Mann-Whitney, p < 0.02) and negatively correlated with both patient overall survival (OS) and cancer-specific survival (CSS; Cox model, p < 0.04). The prognostic value of uPA and uPAR for both OS and CSS was independent of other variables (multivariate Cox model, p < 0. 007). Antisense-uPAR transfected HCT116 cells, which expressed significantly lower levels of total cellular and cell surface uPAR proteins and uPA-binding activity compared with either wild-type or cells transfected with vector alone (Bonferroni, p < 0.05/3), consistently showed decreased invasiveness through Matrigel (Bonferroni, p < 0.05/3) and decreased metastasis formation in nude mice (Fisher, p < 0.05). Our data suggest that uPAR and uPA are independent prognostic factors in CRC; anti-uPAR treatment, which affects both uPAR and uPA levels, may have potential for new treatment of the disease.

Evidence for post-transcriptional down-regulation of the apoptosis-related gene bcl-2 in human colorectal cancer.

This retrospective study was undertaken to investigate the expression of bcl-2 protein and messenger RNA in colorectal cancer (CRC). Immunohistochemical analysis using a monoclonal mouse antibody to the bcl-2 protein and in situ hybridization using a digoxigenin-labelled bcl-2 cRNA probe were carried out on formalin-fixed and paraffin-embedded specimens from 53 colorectal adenocarcinomas, 27 liver secondaries, and 60 adenomas with various degrees of dysplasia. Normal human tonsil sections were used as positive controls. Expression of bcl-2 protein and of messenger RNA was evaluated semiquantitatively. The expression of bcl-2 protein was gradually and significantly lost during the progression from moderately dysplastic adenoma to primary CRC (moderate/severe dysplasia: Mann-Whitney U-test, p=0.0001; severe dysplasia/primary CRC: p=0.027), whereas the cellular expression of bcl-2 mRNA was gradually increased during the dysplasia/adenoma-carcinoma neoplastic sequence. These observations suggest that in a proportion of colorectal cancer cases, the bcl-2 proto-oncogene expression may be down-regulated at a post-transcriptional level.

Hypomagnesemia and hypocalcemia after thyroidectomy: prospective study.

Hypomagnesemia after total thyroidectomy has not been studied extensively. Our anecdotal experience suggests that it may be important in some patients after thyroid excision. The hypomagnesemic hypocalcemic syndrome has been described in other disease states in which a state of functional hypoparathyroidism exists. This study was designed to determine the incidence of hypomagnesemia after total thyroidectomy and relate it to hypocalcemia and symptoms during the postoperative period. A prospective study of all patients undergoing total thyroidectomy between September 1994 and July 1996 was performed. Patient data, thyroid function, retrosternal extension, initial versus reoperative surgery, operative details, parathyroid resection, and pathology were recorded. Calcium, magnesium, electrolytes, blood count, liver function tests, and albumin were measured prior to surgery and twice daily during the postoperative period. Fifty patients underwent total thyroidectomy: 68% were hypocalcemic, 72% were hypomagnesemic, and 36% were symptomatic during the postoperative period. Hypomagnesemia and gender were associated with hypocalcemia. Volume of fluid and neck dissection were associated with low magnesium levels. Hypomagnesemia and parathyroid resection were risk factors for symptoms after thyroidectomy. No patients developed permanent hypoparathyroidism. Transient hypocalcemia and hypomagnesemia occur frequently after total thyroidectomy. The etiology of this phenomenon is probably multifactorial. Patients are more likely to be symptomatic when both cations are low, and attempting to correct only hypocalcemia may prolong symptoms. It is important to monitor both calcium and magnesium levels after total thyroidectomy and to correct deficiencies to facilitate prompt resolution of symptoms.

Genomic alterations (LOH, MI) on chromosome 17q21-23 and prognosis of sporadic colorectal cancer.

Genomic alterations at the long arm of chromosome 17, and in particular at the nm23 locus, are still controversial in colorectal cancer (CRC). Our aim was to investigate the possible relationship of loss of heterozygosity (LOH) and microsatellite instability (MI), at 4 microsatellite loci spanning the 17q21-23 region, to the risk of liver metastasis and nm23 protein expression. Genomic DNA extracted from 58 primary and 54 liver secondary formalin-fixed and paraffin-embedded CRCs was obtained from 82 patients. A fluorescent PCR coupled with an automated DNA sequencer was applied. Increasing fraction of loci showing LOH was positively associated with risk of liver metastases (logrank test for trend, p = 0.005); this remained independent after adjusting to T-stage (Cox regression, p = 0.022), N-stage (p = 0.007), or Dukes' stage (p = 0.012). Conversely, increasing frequency of MI was associated with a reduced risk of liver metastases in Dukes' B tumours (logrank test for trend, p = 0.032). When comparing 30 primary and matched liver secondary lesions, we found concordant genomic alteration in 72% (NME1) to 43% (D17S579). Finally, we observed a trend in association between the proportion of loci with LOH and nm23 positivity (chi2 test for trend, p = 0.024). Our findings suggest that genomic alterations in the 17q21-23 region may affect prognosis of CRC as well as regulation of the nm23 protein expression via an unknown underlying mechanism.

Pelvic exenteration for advanced pelvic malignancy.

Pelvic exenteration is a demanding, yet potentially curative operation, for patients with advanced pelvic cancer. The majority will present with recurrence after prior surgery and radiotherapy. After exenteration, 5-year survival is 40% to 60% in patients with gynecologic cancer as compared to 25% to 40% for patients with colorectal cancer. Physiologic age and absence of co-morbidities appear to be more important when selecting patients for exenteration than chronological age. Careful pre-operative staging, including either computed tomography (CT) scan or magnetic resonance imaging (MRI), usually will identify patients with distant metastases, extrapelvic nodal disease, or disease involving the pelvic sidewall (which generally precludes surgery). The recent application of intra-operative radiotherapy or postoperative high-dose brachytherapy for patients with more advanced pelvic disease, which may include sidewall involvement, may expand the standard indications for exenteration. However, the intent of this procedure, with or without radiotherapy, should be resection of all tumor with the aim of cure since the place of palliative exenteration is controversial at best. The operative details of exenteration are presented, as are two surgical approaches to composite resection of pelvic structures in continuity with sacrectomy. Filling the pelvis with large tissue flaps, usually a rectus abdominus flap, has decreased morbidity rates, particularly with small bowel complications. Peri-operative mortality is usually 5% to 10%, and significant morbidity occurs in over 50% of patients. Restorative techniques for both urinary and gastrointestinal tracts can diminish the need for stomas and, along with vaginal reconstruction, can significantly improve quality of life for many patients after exenteration. These advances in surgery and radiotherapy help make the procedure a viable option for patients with otherwise incurable pelvic malignancy.

Voice changes and thyroid surgery: is pre-operative indirect laryngoscopy necessary?

BACKGROUND: Indirect laryngoscopy (IDL) is often performed prior to thyroid surgery to detect pre-existing vocal cord pathology. METHODS: A retrospective chart review of 201 patients undergoing thyroid surgery at the Prince of Wales Hospital was undertaken in order to study the patterns of pre-operative and postoperative voice changes and IDL findings. RESULTS: A total of 9% of patients had pre-operative voice symptoms, and 22% of this group had abnormalities detected on pre-operative IDL. Of 160 documented IDL, 4% revealed vocal cord pathology in asymptomatic patients, including an asymptomatic recurrent laryngeal nerve palsy. CONCLUSIONS: Indirect laryngoscopy remains a useful but flawed pre-operative screening tool for patients with voice symptoms, but the literature suggests that more advanced phoniatric tests will provide superior diagnostic sensitivity. The role of routine pre-operative laryngoscopy for asymptomatic patients is of debatable value.

Protein markers in colorectal cancer: predictors of liver metastasis.

OBJECTIVE: To assess the significance of the expression of five protein markers (nm23, p53, c-erbB-2, u-PA, and VEGF) to the development of metastasis in colorectal cancer. SUMMARY BACKGROUND DATA: The metastatic cascade is a complex multistep process involving several genetic alterations, angiogenesis activation, and tissue proteolysis. Although the prognosis of colorectal cancer depends on the stage of the tumor, the development of metastasis is difficult to predict. METHODS: Paraffin-embedded specimens of 58 patients who underwent surgery for colorectal cancer were retrospectively analyzed by immunohistochemistry, and the coexpression of these protein markers was related to patient outcome. RESULTS: The risk of developing liver secondaries was correlated with the expression of nm23 protein (p < 0.0001); this was also the case in those patients with Dukes' stage B showing positive nm23 immunostaining (p = 0.006). The determination of the number of positive markers or the cumulative intensity score did not improve the predictive value over and above that of nm23 protein alone. CONCLUSION: Expression of nm23 protein is correlated with the risk of developing liver metastasis. Its evaluation alone may help to determine which patients who have undergone apparently curative resection of a colorectal cancer have an increased risk of liver recurrence, especially those with Dukes' stage B tumors who might be considered for adjuvant chemotherapy.

Extremity soft tissue sarcoma: factors predictive of local recurrence and survival.

BACKGROUND: To identify risk factors for local recurrence and overall survival in patients with extremity soft tissue sarcoma. METHODS: A retrospective study was performed of all patients with extremity soft tissue sarcoma treated at the Combined Surgical Oncology Clinic in the Institute of Oncology at Prince of Wales Hospital between 1972 and 1992. Variables analysed included clinical presentation, patient characteristics, tumour characteristics, treatment factors and outcome. RESULTS: One hundred and nineteen patients were eligible for the study. The most common type of presentation was with a painless mass, usually in the thigh. Local control rates at 5 and 10 years were 75% and 73%. Local control was higher in patients who had more radical surgery and in those who received adjuvant radiotherapy. Tumour size and high grade were independent risk factors for poorer survival. Patients over 50 had poorer survival than younger patients and those who presented with recurrent tumours also tended to have poor survival compared to patients presenting de novo. The respective 5- and 10-year survival rates were 65% and 62%. CONCLUSION: This study suggests that local control of extremity soft tissue sarcoma is improved by radical surgery and by the addition of radiotherapy when more conservative procedures are used. Overall survival appeared to be largely determined by patient (age, recurrent presentation) and tumour characteristics (grade, size).

Australia's breast surgery workload is changing: comparison of a metropolitan and a rural hospital.

BACKGROUND: Breast cancer is a common disease in our community and its incidence is increasing. As a result of the improvements in community awareness and introduction of screening, patients are being diagnosed with earlier breast cancer and with a higher incidence of pre-invasive disease. Improvements in radiology, often coupled with minimally invasive diagnostic modalities, have lessened the requirement for open diagnostic biopsies and also reduced the number of operations for benign breast disease. METHODS: An audit of the surgical workload at Prince of Wales/Prince Henry Hospitals and Tamworth Base Hospital was conducted to document and compare the above changes in the metropolitan and rural settings. This study was conducted between 1987 and 1996 to assess the effect of screening and improved technology over a 10-year period. RESULTS: The study found that a high percentage of malignant lesions are being diagnosed by fine-needle aspiration biopsy (FNAB) with a corresponding reduction in open biopsy rate at the Prince of Wales Hospital. There is a smaller percentage of benign operations in both settings with a reduction of equal proportion. The reporting of the pathology specimens has markedly improved at both institutions. There has been a reduction in the number of patients having modified radical mastectomy and there has been a corresponding increase in breast conservation surgery especially at the Prince of Wales/Prince Henry Hospitals, although there was an unexpectedly high incidence of breast conservation surgery at Tamworth Base Hospital in 1987. In 1996 the rates of breast conservation surgery were the same in both hospitals. CONCLUSIONS: There are minimal differences in the quality of surgical care being offered to patients at the Tamworth Base Hospital compared with the Prince of Wales Hospital and both institutions are within reach of the accepted best management practices available.

Re-engineering the elective surgical service of a tertiary hospital: a historical controlled trial.

OBJECTIVE: To study the clinical effects of re-engineering the processes associated with elective surgery. DESIGN: A prospective, historical controlled trial. Control patients were enrolled from March 1995 to January 1996, and postintervention patients from February 1996 to October 1996. SETTING: A major teaching, tertiary care hospital (Prince of Wales Hospital, Sydney). PATIENTS: 224 patients (123 before and 101 after the intervention) undergoing elective herniorrhaphy of laparoscopic cholecystectomy who lived in the local area. INTERVENTION: Introduction of a re-engineered surgical service consisting of preadmission assessment and education, admission on day of surgery, and postacute care after discharge. There were no changes to the operative methods or infection control procedures. MAIN OUTCOME MEASURES: Length of stay, operative complications, pain scores and patient satisfaction. RESULTS: The risk of a patient suffering one or more complications was reduced in the postintervention group (postintervention v. control patients: 25.7% v. 38.2%; relative risk [RR], 0.66; 95% confidence interval [CI], 0.44-0.98; P = 0.035) because of a reduced risk of wound infections (5.0% v. 16.3%; RR, 0.30; 95% CI, 0.12-0.78; P = 0.0075). Other complications (perioperative or postoperative) and pain scores were unchanged. Patients treated by the re-engineered service had a significantly shorter length of stay, reported a higher level of satisfaction with the preoperative and postdischarge care, and were more likely to say that they would have the same treatment again (92.9% v 82.6%; P = 0.037). CONCLUSIONS: Re-engineering surgical services, with an associated reduction in length of stay, does not lead to a deterioration in care and may decrease postoperative complications and increase patient satisfaction.

Vascular endothelial growth factor expression is reduced in liver metastasis from colorectal cancer and correlates with urokinase-type plasminogen activator.

We undertook a retrospective study to investigate the correlation between the expression of vascular endothelial growth factor (VEGF) and urokinase-type plasminogen activator (u-PA) proteins with progression of colorectal carcinoma (CRC). Immunohistochemical analyses using antibodies against VEGF and u-PA were carried out on archival specimens of 58 human colon carcinomas, 30 liver secondaries and 20 adenomas. Expression of VEGF was significantly reduced in the metastatic liver tumours compared with primary ones (Wilcoxon test, P = 0.002), suggesting VEGF activity to be secondarily down-regulated once the tumour cells reach the hepatic parenchyma. There was no strong evidence from our data that the level of VEGF or u-PA in the primary tumour could predict risk of liver metastasis or survival duration. VEGF and u-PA expression were positively correlated in primary CRC suggesting that both proteins may interact in vivo (chi-square test, P = 0.019) in tumour progression.

Correlates of urokinase-type plasminogen activator in colorectal cancer: positive relationship with nm23 and c-erbB-2 protein expression.

We undertook a study to analyze the expression of urokinase-type plasminogen activator (u-PA) protein in colorectal cancer (CRC) and to compare it with c-erbB-2 (HER2/neu) and nm23 protein expression. Paraffin-embedded specimens from 58 patients with CRC were retrospectively collected. Immunohistochemical staining of u-PA, c-erbB-2, and nm23 was quantitatively evaluated using a color video image analysis (color VIA) technique. No correlation was found between u-PA expression and tumor stage, age, sex, or tumor site. Although there was no evidence from our data that the level of u-PA in the primary tumors could predict risk of liver metastasis or survival duration, CRC showing overexpression of u-PA (above 85 pixels) had a worse prognosis (P = 0.013). There were significant positive correlations among all three u-PA, c-erbB-2, and nm23 proteins (u-PA vs. c-erbB-2, P = 0.003; u-PA vs. nm23, P < 0.001; c-erbB-2 vs. nm23, P = 0.001), suggesting that, in vivo, all proteins interact or are similarly regulated.

The role of the journal club in surgical training.

BACKGROUND: The development of skills in critical appraisal of the medical literature is an important aspect of surgical training. METHODS: At the Prince of Wales Hospital a journal club has been conducted for more than 5 years to improve the registrars' training in this area. A questionnaire was circulated regarding the success of the journal club at achieving adequate review of the important current literature, development of critical appraisal skills by registrars and providing a convivial social gathering. RESULTS: A total of 28 out of 39 current or previous journal club members responded to the questionnaire. Twenty-three of the respondents felt that the journal club provided a good to excellent review of current literature, 26 felt that the journal club facilitated development of critical appraisal skills and all 28 said that the journal club was a convivial social forum. Eight research projects developed from journal club reviews, 19 of the respondents reported that their clinical practice had changed, and 19 had been stimulated to further review a topic as a result of the journal club. Many of the respondents had specific criticisms of the journal club, and these have been used to improve the journal club format. CONCLUSIONS: The present study has highlighted the strengths and weaknesses of our journal club. The journal club is a valuable component of surgical education.

Overexpression of nm23 protein assessed by color video image analysis in metastatic colorectal cancer: correlation with reduced patient survival.

The function and prognostic significance of the nm23 gene is controversial in colorectal cancer (CRC). The aim of this study was to determine if nm23 protein expression correlated with the subsequent development of liver metastasis. Paraffin-embedded sections of 30 metastasizing CRC primaries and their subsequently resected liver secondaries were compared with those of 28 nonmetastasizing CRCs, 20 adenomas, and 20 cases of normal colonic mucosa. Expression of nm23 protein, assayed by immunohistochemistry, was measured using a standard semiquantitative scaling system and compared with a microcomputerbased color video image analysis (VIA). There was good correlation between color VIA and semiquantitative evaluation of nm23 immunoreactivity, confirming the validity of quantitative analysis (Pearson's r = 0.88; p < 0.001). Metastasizing CRC primaries and secondaries overexpressed nm23 protein when compared with the other clinical groups, particularly nonmetastasizing CRC (Student's t-test, p < 0.001). Furthermore, more nm23 immunoreactivity was associated with a higher risk of death from CRC (log-rank test, p = 0.002). These results suggest that overexpression of nm23 is highly associated with liver metastases from CRC and reduced survival.

In vivo overexpression of c-erbB-2 oncoprotein in xenografts of mice implanted with human colon cancer lines.

We have previously shown that c-erbB-2 oncoprotein encoded by the erbB-2 gene is overexpressed in human colorectal cancers that metastasis compared to those that are cured by surgery. To determine whether c-erbB-2 is also differentially expressed in vivo in metastasising and non-metastasising tumours, we developed models of colorectal cancer growth in nude mice. Human colon cancer cell lines, HCT116, KM12SM, LIM1215 and SW480, were injected into the caecum after characterising their morphology, doubling time, DNA flow-cytometry and expression of c-erbB-2. Six weeks later, xenografted tissues were fixed for histological analysis and detection of c-erbB-2 by immunohistochemistry, 78% (21/27) of mice developed caecal cancers. The caecal tumours derived from HCT116, KM12SM or LIM1215 were highly metastatic; 67 to 100% of them had liver metastases and lymph node involvement and 33 to 75% had lung tumours. Most of the tumours were c-erbB-2-positive. In contrast SW480 caecal tumours had only 33% lymph node involvement, but not liver or lung metastases. Only one SW480 caecal tumour and one lymph node metastasis expressed c-erbB-2. C-erB-2 was more frequently expressed in xenografted tissues in colon cancer primaries and secondaries of the highly metastatic cells (HCT116, KM12SM and LIM1215) compared to the cells (SW480) giving predominantly local growth. Our results suggest that c-erbB-2 gene may play an important role in the development of metastasis from colorectal cancer.