Expression and prognostic value of epithelial-to-mesenchymal transition and cancer stem cellmarkersin primary lesions and liver metastases of colorectal cancers

Cancer stem cells (CSCs) and epithelial mesenchymal transition (EMT) markers are considered useful indicators associated with metastasis and prognosis of colorectal cancers (CRCs). However, only a few studies have focused on the expression of these useful markers in metastases. Metastasectomy is widely used in advanced CRCs, and thus the postoperative prognostic factors are worth investigating. The present study investigated the consistency and differences of target proteins between primary and metastatic lesions of colorectal cancer, and discussed the prognostic indicators following resection of colorectal liver metastases. Clinical data of 56 patients with liver metastases from colorectal cancer were collected and the expression levels of target proteins (Ki-67, CD133, CD44, Snail, E-cadherin and β-catenin) were detected in primary tumor and matched liver metastases via immunohistochemistry analysis. Paired comparison between both tissue types was performed. The prognostic values of the target proteins for resectable colorectal cancer liver metastases were assessed. No significant differences were observed between the primary tissues and metastatic tissues. The consistency rates of these protein expression levels ranged from 51.8–78.6%. The maximum diameter of the liver metastases was <5 cm. Low Snail expression in metastases was associated with a longer overall survival (OS) time following resection of colorectal liver metastases. Furthermore, N0 stage and low carcinoembryonic antigen levels were associated with a longer progression-free survival time. Notably, no significant differences were observed in expression levels of the target proteins between the primary tumors and liver metastases. Taken together, the results of the present study suggest that Snail expression in liver metastases may be used as a novel independent prognostic factor for OS following resection of colorectal liver metastases.     

Tropism between hepatic and pulmonary metastases in colorectal cancers

In metastatic colorectal cancers, tumor cells are disseminated prior to surgical resection of the primary tumor but remain dormant until proper colonization mechanisms are activated. To identify the colonization mechanisms of the metastatic tumors, we conducted a pairwise comparison between primary colorectal cancers and metastatic tumors (n=12 pairs), including six hepatic pairs and six pulmonary pairs. The mRNA levels of 224 genes previously reported to be associated with metastasis, cytokines and angiogenesis were quantitatively determined by PCR arrays. Among them, 27 genes were duplicated or triplicated to show consistent expression. Unsupervised hierarchical clustering of the Ct values of metastasis-related genes revealed that liver metastases were indistinguishable from primary colorectal cancers (n=5/6), whereas lung metastases were highly diversified from one another and from the primary tumors (n=6/6). Cytokines and receptor gene expression array data also confirmed the divergence of pulmonary metastases from primary colorectal cancers (n=6/6). Heat map analyses of ΔCt values of the metastasis-related genes identified a 17-gene tropism signature that was sufficient not only to distinguish liver and the lung metastases, but also reconstituted the clustering of primary tumors with the hepatic metastases (n=17/18). In this pilot experiment, pulmonary metastases were significantly diverged from hepatic metastases that were indistinguishable from primary colorectal cancers. Further genomic and clinical studies are in progress to evaluate the potential of the tropism signature as a therapeutic target to inhibit the colonization of metastatic colorectal cancers.     

Lymphocytic infiltration surrounding liver metastases from colorectal cancer

BACKGROUND AND OBJECTIVES: Tumor infiltrating lymphocytes (TILs) have been recognized as a tumor-host reaction in various primary neoplasms. Although several studies reported TILs surrounding metastatic liver tumors, to the authors' knowledge few evaluations of the clinical significance of such features in patients with colorectal liver metastases have been carried out. METHODS: Forty-one patients who underwent initial hepatic resection for liver metastases from colorectal cancer were studied. Lymphocytic infiltration surrounding metastatic liver tumor was graded as weak or dense according to the mean number of TILs from 10 high-power microscopic fields (< or =50 or >50/HPF). RESULTS: Dense lymphocytic infiltration between the metastatic tumor and hepatic parenchyma was seen in 18 of 41 patients (44%). Histologically, tumor invasion of the portal vein was rare in patients with dense TILs (12%) compared with patients with weak TILs (36%). Patients with dense TILs survived longer than patients with weak TILs after hepatic resection (P = 0.013). Multivariate analysis using the Cox proportional hazard model identified this pathological variable as a significant independent prognostic factor after hepatic resection. CONCLUSIONS: The extent of lymphocytic infiltration between the metastatic nodule and hepatic parenchyma may reflect host defensive activity in the liver and is closely related to prognosis in patients who underwent hepatic resection for liver metastases from colorectal cancer.     

P53 mutations in primary tumors and subsequent liver metastases are related to survival in patients with colorectal carcinoma who undergo liver resection

BACKGROUND: The appearance of p53 mutations in colorectal carcinoma was determined, independent of differentiation and tumor stage of the primary tumors, in relation to the survival of patients who were scheduled to undergo liver resection. METHODS: Tumor material was analyzed for p53 mutations in primary colorectal tumors and subsequent liver metastases from 41 consecutive patients who were scheduled to undergo surgical liver resection. DNA sequencing and immunohistochemical staining of p53 protein within tumor nuclei were performed. RESULTS: Primary tumors displayed p53 mutations within exons 5-9 in 41% of patients. No mutations were found in exons 4, 10, or 11. Forty-one percent of metastatic lesions had the same single mutation that was found in the primary tumor, whereas 11% of metastatic lesions had one additional mutation within exons 5-9; 22% had mutations only in their liver metastases, whereas corresponding primary tumors displayed wild-type p53. None of the patients had mutated p53 in their primary tumor and wild type in their metastases. Survival after undergoing liver resection was correlated negatively (P < 0.05-0.01) with Duke Stages A-D classification of the primary tumors, tumor differentiation, and radicality (> 0.7-0.8 mm) of resected liver metastases. CONCLUSIONS: The presence of p53 mutations in patients with metastatic lesions was related significantly (P < 0.003) to better survival after the patients underwent liver resection compared with patients with wild type p53 in their metastatic lesions. This finding was not related to covariates, such as Duke classification, tumor differentiation, type of liver metastasis, or metastatic radicality during resections. Explanations for this unexpected finding remain unclear, although the authors speculate that occult tumor cells with p53 mutations may be less responsive to growth factor(s) exposure during hepatic regeneration after resection.     

c-erbB-2 protein expression and clinicopathologic features in colorectal cancer

Previous reports showed that breast and gastric cancers overexpressing c-erbB-2 protein have a greater metastatic potential and worse prognosis than tumors in which this protein is not overexpressed. The present study was undertaken to examine the significance of c-erbB-2 protein expression as a prognostic factor in colorectal cancer. Protein expression was examined immunohistologically in colorectal cancer tissue from 149 patients without distant metastasis, from 38 patients with liver metastasis, and from 18 patients with lung metastasis. The c-erbB-2 protein-positive rate was significantly higher in cases with lymphatic vessel invasion in the primary tumor, but it did not correlate with lymph node metastases. Expression of c-erbB-2 did not correlate with any other histologic feature (histologic type, depth of tumor invasion, venous vessel invasion, or the clinical stage). The positive rate in the primary lesion was significantly higher in cases with liver metastasis than in cases without liver metastasis, the positive rate was significantly higher in the hepatic than in the primary lesions. The expression of c-erbB-2 protein in colorectal cancer tissue correlates closely with liver metastasis but not with lymphatic or lung metastases.     

Indication of hepatic resection for metastatic liver tumors from gastric cancer

To clarify the benefit and indication of resection for metastatic liver tumors from gastric cancer, we reviewed the therapeutic outcomes at the Niigata University Medical Hospital and at a referred institution. From January 1982 to April 2004, thirty-nine patients with synchronous and 40 with metachronous liver metastases from gastric cancer had been treated. In synchronous cases, forty percent of the patients had many metastatic tumors in bilateral hepatic lobes and the majority of them had advanced gastric cancer with serosal invasion and widely spread of lymphatic metastases. On the other hand, over 70% of metachronous patients had unilobar or scattered bilobar metastases and only 20% of them accompanied other types of metastases. A survival analysis showed that the prognoses of patients undergoing hepatic resection were statistically better than other treatments in both synchronous and metachronous cases. And there was no evidence for the benefit of palliative gastrectomy. So we conclude that surgical treatment for hepatic metastases from gastric cancer is a beneficial option if all the lesions including the primary and lymphatic ones can be eradicated in limited candidates of synchronous cases and in more candidates of metachronous cases, especially unilobar and a few scattered bilobar metastases.     

Surgical therapy of liver metastases

The liver is the most common site of metastatic disease from both gastrointestinal and extra-intestinal malignancies. Historically, only a minority of patients with colorectal liver metastases were candidates for resection. However, over the past several decades, liver resection has evolved as a safe and potentially curative treatment for hepatic colorectal metastases. The development of active chemotherapy and molecular targeted therapies, together with newer modalities like radiofrequency ablation, have expanded the indications for hepatic resection and improved survival. Selected patients with isolated liver metastases from neuroendocrine tumors, germ cell cancers, ocular melanoma, gastrointestinal stromal tumors (GIST), and breast cancer also may be considered for hepatic surgery.     

Loss of Smad4 expression predicts liver metastasis in human colorectal cancer

Distant metastases represent the major cause of death after curative surgery of colorectal cancer. The aim of this study was to evaluate the role of Smad4 and KRAS genetic alterations in colorectal metastases taking into account both the site (hepatic versus extrahepatic) and the time (synchronous versus metachronous) of recurrence. We examined the immunohistochemical expression of Smad4 and frequency of KRAS mutation in primary colorectal tumors and in their corresponding metastatic tissues. Loss of Smad4 expression was noted in 37% (26/71) of the primary tumors and the corresponding metastases. Absence of Smad4 protein was more frequently observed in hepatic metastases, whether they were metachronous or synchronous, than in extrahepatic metastases (p<0.005). The frequency of KRAS mutations was high in the synchronous and extrahepatic metachronous metastases (68-80%), but was significantly lower in the hepatic metachronous metastases (11%). Our results indicate that absence of Smad4 expression correlated significantly with liver metastases regardless of the time of their occurrence and represents a promising new biomarker to predict liver metastasis in colorectal cancer patients. Therefore, this group of patients could benefit from a specific and appropriate pre- and/or post-operative therapy.     

Predictive value of thymidylate synthase expression in resected metastases of colorectal cancer

Recent investigations have focused on the prognostic value of thymidylate synthase (TS) assessment in metastases of colorectal carcinoma (CRC). In order to evaluate the prognostic impact of TS expression after resection of metastases of colorectal cancer followed by systemic adjuvant chemotherapy, we performed an immunohistochemical characterisation of TS in the primary tumours and in the corresponding radically resected hepatic and pulmonary metastases. An additional objective was to compare the levels of TS in primary and metastatic disease. TS expression was assessed by immunohistochemistry using the monoclonal antibody TS 106. The study population consisted of 60 patients: 48 underwent liver and 12 lung resection. All of them received adjuvant chemotherapy after metastasectomy according to the Mayo Clinic schedule. In the 49 evaluable primary tumours, TS score was high in 53% and low in 47% of patients, while in the 60 metastatic samples TS immunostaining was high in 33% and low in 67%. There was a significantly smaller number of high TS expressors in metastatic than in primary tumours (P<0.04). No correlation was observed between TS expression and the site of the metastasis. TS status did not significantly correlate with the median disease-free interval (DFI) after metastasectomy, although this parameter was longer for patients with low TS immunoreactivity in the resected metastases than for those with high TS lesions (19.6 versus 13.8 months). Patients with high TS levels, however, had a significantly shorter median overall survival (OS) (27.6 months) than those with low TS expression (36.3 months) (P<0.008). TS status in the resected metastases confirmed its independent prognostic value in the multivariate analysis and was the only prognostic marker of OS in the subgroup of patients with resected liver metastases. These results suggest that high TS levels in resected metastases of colorectal cancer are associated with a poor outcome after surgery and 5-FU adjuvant therapy; therefore, a prospective assessment of TS levels in resected colorectal metastases could be useful to define which patients will most likely benefit from 5-FU adjuvant therapy after metastasectomy. Chemotherapeutic agents that target TS may not be the appropriate adjuvant treatment after metastasectomy for patients with a high TS expression in the resected metastases of colorectal cancer.     

Fibrous pseudocapsule of metastatic liver tumors from colorectal carcinoma. Clinicopathologic study of 152 first resection cases

BACKGROUND: The presence of pseudocapsules of liver tumors has been recognized in hepatocellular carcinoma and is known to be a favorable prognostic factor. Although several studies have reported pseudocapsules around metastatic liver tumors, to the authors' knowledge there have been few evaluations of the clinical significance of such features in patients with metastatic colorectal carcinoma. METHODS: A clinicopathologic study was conducted in 152 patients who underwent initial hepatic resection for metastatic colorectal carcinoma. RESULTS: The presence of fibrous tissue between the tumor and the surrounding hepatic parenchyma was noted in 93 of the 152 patients (61%) with colorectal liver metastases. These patients were classified as having a thin pseudocapsule (n = 46) or a thick pseudocapsule (n = 47), according to the number of collagen bundles (< 10 or >/= 10) between the tumor and the hepatic parenchyma in histologic sections. Pathologically, the presence and thickness of the fibrous pseudocapsule were related closely to less invasiveness into adjacent vessels (P = 0.004) and the presence of macroscopic intrabile ductal invasion (P = 0.008). The postresection survival was significantly better in patients with thick or thin pseudocapsules than in those without a pseudocapsule (3-year and 5- year cumulative survival rates of patients with no, thin, and thick pseudocapsules were 41% and 31%, respectively, 71% and 64%, respectively, and 88% and 88%, respectively; P < 0.001). In a multivariate analysis using the Cox proportional hazards model, after adjusting for other potential prognostic factors (vascular invasion, bile ductal invasion, number of tumors, tumor size, and curativeness of surgery), the presence of a fibrous pseudocapsule was an independent predictor of a favorable outcome after hepatic resection. CONCLUSIONS: The presence of fibrous tissue between the tumor and the liver parenchyma was a promising indicator of a better prognosis after resection in patients with colorectal liver metastases.     

结直肠癌肝转移患者预后因素分析

目的：探讨结直肠癌肝转移患者外科治疗后的预后影响因素及临床意义.方法：分析本院1995年1月至2000年12月158例经病理证实、随诊资料完整的结直肠癌肝转移病例临床资料，对影响患者生存的12项因素进行单因素、多因素分析.结果：根治性切除67例（42.4%）、姑息性切除53例（33.5%）、探查术或最佳支持治疗38例（24.1%） 术后化疗82例（51.9%）、术后未化疗76例（48.1%） 切缘阴性132例（83.5%）、切缘阳性26例（16.5%） 中位生存期41个月，5年生存率27.0%.单因素分析表明，外科治疗方式（P=0.013＜0.05）、原发瘤N分期（P=0.003＜0.05）、转移灶大小（P=0.037＜0.05）及分布（P=0.032＜0.05）和切缘（P=0.000＜0.001）、辅助性治疗（P=0.041＜0.05）为预后影响因素 多因素回归分析显示，仅有原发瘤N分期（P=0.004＜0.05）为预后的独立影响因素，淋巴结转移的相对危险度为2.086.结论：结直肠癌肝转移的根治性切除是患者获得长期生存的有效治疗手段 对于结直肠癌肝转移患者应恰当选择病例，力求一期根治性切除 不适合一期根治性切除者，应采用新辅助化疗手段，降级肿瘤的临床病理分期，以期提高根治性切除率，提高患者生存期.     

Assessment of K-ras, Smad4 and p53 gene alterations in colorectal metastases and their role in the metastatic process

To date there is no genetic marker that gives accurate information on the prognostic impact for patients with colorectal cancer. A particular clone, not detected in the tumor, could be responsible for the metastatic process. To overcome this problem, genetic alterations were analyzed in metastatic tissues from 58 patients who developed metastases after curative surgery for colorectal cancer. K-ras, p53 and Smad4 alterations were observed in respectively 38, 60 and 27% of the metastases. These frequencies are similar to the ones reported in primary colorectal tumors. Thus, these genetic alterations cannot be used as prognostic biomarkers in patients with colorectal cancer. The metastases were stratified into 3 groups, according to the metastatic localization. K-ras mutations were detected in respectively 75, 26 and 11% of the distant, peritoneal and liver metastases. Loss of Smad4 expression was observed more frequently in the liver (62%) than in other metastases (13%). These results suggest that the genetic changes of the tumor cells indicate the location of the metastases and thus, the route of metastatic spread.     

Current role of hepatic artery infusion and isolated liver perfusion for the treatment of colorectal cancer liver metastases

There are many treatment options for patients with metastatic colorectal carcinoma confined to the liver. Surgical resection alone can result in significant prolongation of survival in patients with favorable prognostic factors. Randomized studies of hepatic artery infusion therapy after complete resection of liver metastases have demonstrated improvements in hepatic recurrence-free survival but no impact on overall survival. Randomized trials evaluating the treatment of unresectable disease with hepatic artery infusion therapy have demonstrated higher response rates (31%-50%) than those seen with systemic chemotherapy (8%-20%) but no survival benefit. Vascular isolation and perfusion of the liver with chemotherapy with or without biologic agents under hyperthermic conditions is another regional modality that has been explored for the treatment of unresectable colorectal cancer liver metastases. Large series report high partial response rates (68%-77%), with responses being achieved in patients with advanced tumor burden and in those who have disease progression through prior treatment of hepatic metastases.     

Tissue inhibitor of matrix metalloproteinase‐1 expression in colorectal cancer liver metastases is associated with vascular structures

Metastatic growth by colorectal cancer cells in the liver requires the ability of the cancer cells to interact with the new microenvironment. This interaction results in three histological growth patterns of liver metastases: desmoplastic, pushing, and replacement. In primary colorectal cancer several proteases, involved in the degradation of extracellular matrix components, are up‐regulated. In liver metastases, their expression is growth pattern dependent. Tissue inhibitor of matrix metalloproteinase‐1 (TIMP‐1) is a strong prognostic marker in plasma from colorectal cancer patients, with significant higher levels in patients with metastatic disease. We therefore wanted to determine the expression pattern of TIMP‐1 in primary colorectal cancers and their matching liver metastases. TIMP‐1 mRNA was primarily seen in α‐smooth‐muscle actin (α‐SMA)‐positive cells. In all primary tumors and liver metastases with desmoplastic growth pattern, TIMP‐1 mRNA was primarily found in α‐SMA‐positive myofibroblasts located at the invasive front. Some α‐SMA‐positive cells with TIMP‐1 mRNA were located adjacent to CD34‐positive endothelial cells, identifying them as pericytes. This indicates that TIMP‐1 in primary tumors and liver metastases with desmoplastic growth pattern has dual functions; being an MMP‐inhibitor at the cancer periphery and involved in tumor‐induced angiogenesis in the pericytes. In the liver metastases with pushing or replacement growth patterns, TIMP‐1 was primarily expressed by activated hepatic stellate cells at the metastasis/liver parenchyma interface. These cells were located adjacent to CD34‐positive endothelial cells, suggesting a function in tumor‐induced angiogenesis. We therefore conclude that TIMP‐1 expression is growth pattern dependent in colorectal cancer liver metastases. © 2015 The Authors. Molecular Carcinogenesis published by Wiley Periodicals, Inc.     

Hepatic disseminated tumor cells in colorectal cancer UICC stage 4 patients: prognostic implications

Approximately 30-50% of all colorectal cancer patients with a resectable primary tumor will subsequently develop metastatic disease due to tumor cell dissemination. In the case of limited solid hepatic metastasis, resection of the primary tumor and the respective hepatic metastasis can be curative. Our aim was to evaluate the incidence of hepatic DTC in patients with solid liver metastasis and to describe their prognostic impact. Therefore, we applied a sensitive PCR-RFLP assay detecting one K-ras mutant among one million wild-type cells. Tumor tissue and liver biopsies from 32 colorectal cancer patients staged UICC 4 undergoing palliative surgery could be obtained intra-operatively and were thereupon screened for the presence of hepatic DTC. The primary tumor of 16 patients (50%) harbored a K-ras mutation and survival of K-ras positive patients was reduced as compared to K-ras negatives (P=0.039). In 8 of the patients (50%) with a K-ras mutated primary, no hepatic DTC were detected, whereas the liver of the remaining 8 patients (50%), showed a coincidence of solid liver metastasis and hepatic DTC. Median survival of patients with solid liver metastasis and hepatic DTC was decreased as compared with patients without any hepatic DTC burden (median survival 165 vs. 240 days; log-rank P=0.951). A subgroup analysis revealed that survival was significantly decreased in the case of bilobal DTC affection as compared with monolobal hepatic DTC affection (median survival 68 vs. 355 days; log-rank P=0.002). We conclude that the detection of hepatic DTC is a powerful prognostic factor. Furthermore, bilobal hepatic DTC involvement might be a contraindication for the resection of solid liver metastasis.     

Microwave coagulation therapy for multiple hepatic metastases from colorectal carcinoma

BACKGROUND: Compared with other treatments, microwave coagulation is a relatively less invasive treatment for various kinds of solid tumors. Although its effectiveness in primary hepatocellular carcinoma has been shown, its effectiveness in the treatment of hepatic metastases from colorectal carcinoma has been unclear. The aim of this study was to evaluate its effectiveness in the treatment of multiple hepatic metastases from colorectal carcinoma by comparing this technique with that of hepatic resection. METHODS: Thirty patients with multiple metastatic colorectal tumors in the liver who were potentially amenable to hepatic resection were randomly assigned to treatment with microwave coagulation (14 patients) or hepatectomy (16 patients). Tumors in the microwave group were coagulated after laparotomy at an output of 60-100 W for 2-20 minutes under the guide of ultrasonography, whereas tumors in the hepatectomy group were treated with lobectomy, segmentectomy, subsegmentectomy, and/or wedge resection. RESULTS: One-, 2-, and 3-year survival rates and mean survival times were 71%, 57%, 14%, and 27 months, respectively, in the microwave group, whereas they were 69%, 56%, 23%, and 25 months, respectively, in the hepatectomy group. The difference between these two groups was statistically not significant (P = 0.83). On the other hand, the amount of intraoperative blood loss in the microwave group (360 +/- 230 mL) was smaller than that in the hepatectomy group (910 +/- 490 mL, P < 0.05). Blood transfusion was necessary for 6 patients in the hepatectomy group, but it was not necessary in the microwave group. CONCLUSIONS: Microwave coagulation therapy is suggested to be equally effective as hepatic resection in the treatment of multiple (two to nine) hepatic metastases from colorectal carcinoma, whereas its surgical invasiveness is less than that of hepatic resection.     

Hepatic cryotherapy and regional chemotherapy with or without resection for liver metastases from colorectal carcinoma: how many are too many?

BACKGROUND: The number of hepatic metastases for which resection or ablation is appropriate remains controversial. METHODS: A retrospective analysis was performed of prospectively collected data from patients with liver metastases from colorectal carcinoma who underwent hepatic cryotherapy and hepatic arterial chemotherapy (HAC) with or without undergoing resection. Patients routinely had preoperative bone scans, chest computed tomography (CT) scans, and abdominal angio-CT scans. Positron emission tomography scans were unavailable. All patients were followed until June 2002 or until death occurred. Kaplan-Meier and Cox regression methods were used to evaluate the impact of 17 potentially prognostic factors on survival. RESULTS: One hundred seventy-two patients who underwent hepatic cryotherapy and HAC with or without undergoing liver resection for in situ eradication of metastases formed the basis of this report. One patient (0.6%) died postoperatively from myocardial infarction. The morbidity rate was 27.9%. The median survival was 28 months (range, 0-98 months). The factors age < or = 50 years, well-differentiated or moderately differentiated primary tumor, small cryolesions (<3.5 cm), complete eradication of extrahepatic metastases at cryotherapy, and low preoperative carcinoembryonic antigen (CEA) levels were associated independently with a favorable outcome. In addition, a univariate analysis showed that the absence of untreated extrahepatic disease at laparotomy, postoperative CEA normalization, and a large decline in CEA levels were significant statistically. The number of lesions was not prognostic. One hundred forty-six patients (84.9%) who underwent a complete operation had 1-year, 2-year, 3-year, 4-year, and 5-year survival rates of 89%, 65%, 41%, 24%, and 19%, respectively. The median survival of patients with 1 metastasis, 2 metastases, 3 metastases, 4 metastases, 5 metastases, 6 or 7 metastases, and 8-12 metastases were 32 months, 29 months, 30 months, 31 months, 27 months, 37 months, and 21 months, respectively (P=0.7859). Twenty-five patients had 6 or 7 lesions, and their 5-year survival rate was 25%. CONCLUSIONS: When all colorectal hepatic lesions were eradicated, the numbers of hepatic metastases were not prognostic of survival in patients with liver metastases from colorectal carcinoma.     

High expression of PRL-3 promotes cancer cell motility and liver metastasis in human colorectal cancer: a predictive molecular marker of metachronous liver and lung metastases.

PURPOSE: Overexpression of PRL-3 has been implicated in colorectal cancer metastases. We investigated the significance of PRL-3 expression in the progression and development of colorectal cancer. EXPERIMENTAL DESIGN: We transfected PRL-3-specific small interfering RNA into human colon cancer DLD-1 cells and analyzed its effect on proliferation, motility, and hepatic colonization. Using an in situ hybridization method, we examined the levels of PRL-3 expression in both primary (177 cases) and metastatic (92 cases) human colorectal cancers and elucidated the relationships with clinicopathological parameters including the incidence of metachronous liver and/or lung metastasis after curative surgery for primary tumor. RESULTS: Transient down-regulation of PRL-3 expression in DLD-1 cells abrogated motility (in vitro) and hepatic colonization (in vivo), but no effect on the proliferation of these cells was observed. In human primary colorectal cancers, the frequency of up-regulated PRL-3 expression in cases with liver (84.4%) or lung (88.9%) metastasis was statistically higher than that in cases without either type of metastasis (liver, 35.9%; lung, 42.3%). In metastatic colorectal cancer lesions, high expression of PRL-3 was frequently detected (liver, 91.3%; lung, 100%). Interestingly, metachronous metastasis was observed more frequently in the cases with high PRL-3 expression (P < 0.0001). CONCLUSIONS: These results indicate that PRL-3 expression in colorectal cancers may contribute to the establishment of liver metastasis, particularly at the step in which cancer cells leave the circulation to extravasate into the liver tissue. In addition, PRL-3 is expected to be a promising biomarker for identifying colorectal cancer patients at high risk for distant metastases.     

Morphologic analysis of microvessels in colorectal tumors with respect to the formation of liver metastases.

BACKGROUND AND OBJECTIVES: Overexpression of VEGF and proliferation of microvessels are strongly related to liver metastases, however, morphologic analyses of microvessels in liver metastases have not been reported. The purpose of the present study was to examine the correlation between liver metastases and the diameters of microvessel lumens in the tumor tissue. METHODS: Fifty-nine patients with liver metastases from colorectal cancers and 112 patients who underwent curative colorectal resection and survived without any recurrence were reviewed. Microvessel density (MVD) and the diameters of the lumens of individual microvessels were assessed. RESULTS: There was a significant difference in terms of the mean MVD of primary tumors between patients with liver metastases and those without liver metastases. The numbers of patients with liver metastases who had microvessels 100-200 microm in diameter and microvessels more than 200 microm in diameter were significantly greater than patients without liver metastases. Microvessels with lumens more than 100 microm in diameter were not detected in the liver metastatic lesion. CONCLUSION: Large microvessels in the primary tumor favor intravasation of cancer cells.     

Prognostic factors for cryotherapy of colorectal liver metastases.

BACKGROUND: Cryotherapy is a local ablative treatment option for non-resectable liver tumours. We aimed to identify prognostic indicators, that may allow better selection or stratification for adjuvant therapies of patients. METHODS: Fifty-five patients had cryotherapy for colorectal liver metastases. The patient-, tumour- and operative details were recorded prospectively. Mean follow up was 24 months. A uni- and multivariate analysis for possible prognostic factors was performed. RESULTS: There was a trend towards better survival for patients with unilobar liver metastases, preoperative serum levels of carcinoembrional antigen (CEA) not exceeding 20 ng/ml and patients undergoing 'R0'-treatment. Patients with multiple or large (>4 cm) liver metastases, patients undergoing cryotherapy combined with liver resection and patients receiving blood transfusion intraoperatively, especially when exceeding 4 units packed red cells, had a significantly impaired survival in univariate analysis. In multivariate analysis (Cox regression) the amount of intraoperative blood transfusion was the only independent prognostic indicator. CONCLUSION: Intraoperative blood transfusion has a negative impact on survival following hepatic cryotherapy for colorectal liver metastases and should be avoided by refinement of surgical technique whenever possible. Patients with multiple liver metastases or metastases of more than 4 cm in size have an impaired prognosis-therefore trials of adjuvant therapies following hepatic cryotherapy for colorectal liver metastases should include number and size of metastases for stratification of patient groups.