New nomograms to predict overall and cancer-specific survival of angiosarcoma.

OBJECTIVE: This study was designed to establish and validate promising and reliable nomograms for predicting the survival of angiosarcoma (AS) patients. METHODS: The Surveillance, Epidemiology, and End Results database was queried to collect the clinical information of 785 AS patients between 2004 and 2015. Data were split into a training cohort (n = 549) and a validation cohort (n = 236) without any preference. Univariate Cox and multivariate Cox regression analyses were performed to analyze the clinical parameters. Independent prognostic factors were then identified. Two nomograms were constructed to predict overall survival (OS) and cancer-specific survival (CSS) at 3 and 5 years. Finally, the models were evaluated using concordance indices (C-indices), calibration plots, and decision curve analysis (DCA). RESULTS: Based on the inclusion and exclusion criteria, 785 individuals were included in this analysis. Univariate and multivariate Cox regression analyses revealed that age, tumor size, and stage were prognostic factors independently associated with the OS of AS. Tumor site, tumor size, and stage were associated with the CSS of AS. Based on the statistical results and clinical significance of variables, nomograms were built. The nomograms for OS and CSS had C-indices of 0.666 and 0.654, respectively. The calibration curves showed good agreement between the predictive values and the actual values. DCA also indicated that the nomograms were clinically useful. CONCLUSION: We established nomograms with good predictive ability that could provide clinicians with better predictions about the clinical outcomes of AS patients.

Low expression of CD80 predicts for poor prognosis in patients with gastric adenocarcinoma.

AIM: To study the expression and prognostic significance of CD80 in patients with gastric adenocarcinoma. Materials & methods: Real-time quantitative PCR, western blot and immunohistochemistry were performed to detect the expression of CD80 in gastric cancer tissues and matched adjacent normal tissues. Double immunohistochemical staining was performed to preliminary examine the relationship between CD80+ cells and CD8+ cytotoxic T lymphocytes. RESULTS: The expression of CD80 was downregulated in tumor tissues compared with normal tissues (p = 0.002). Immunohistochemistry analysis showed that 49 (39.8%) of 123 patients with gastric cancer demonstrated reduced CD80 expression, which was correlated with the tumor differentiation grade. CONCLUSION: Our data suggest that reduced CD80 expression independently predicts a poor prognosis in patients with gastric adenocarcinoma.

Safety and activity of PD-1 blockade-activated DC-CIK cells in patients with advanced solid tumors.

Cytokine-induced killer (CIK) cells that are stimulated using mature dendritic cells (DCs), referred to as (DC-CIK cells) exhibit superior anti-tumor potency. Anti-programmed death-1 (PD-1) antibodies reinvigorate T cell-mediated antitumor immunity. This phase I study aimed to assess the safety and clinical activity of immunotherapy with PD-1 blockade (pembrolizumab)-activated autologous DC-CIK cells in patients with advanced solid tumors. Patients with selected types of advanced solid tumors received a single intravenous infusion of activated autologous DC-CIK cells weekly for the first month and every 2 weeks thereafter. The primary end points were safety and adverse event (AE) profiles. Antitumor responses, overall survival (OS), progression-free survival (PFS) and cytolytic activity were secondary end points. Treatment-related AEs occurred in 20/31 patients. Grade 3 or 4 toxicities, including fever and chills, were observed in two patients. All treatment-related AEs were reversible or controllable. The cytotoxicity of DC-CIK cells induced up-regulation of PD-L1 expression on autologous tumor cells. When activated using pembrolizumab ex vivo, DC-CIK cells exerted superior antitumor properties and elevated IFN-γ secretion. Objective responses (complete or partial responses) were observed in 7 of the 31patients.These responses were durable, with 6 of 7 responses lasting more than 5 months. The overall disease control rate in the patients was 64.5%. At the time of this report, the median OS and PFS were 270 and 162 days, respectively. In conclusions, treatment with pembrolizumab-activated autologous DC-CIK cells was safe and exerted encouraging antitumor activity in advanced solid tumors. A larger phase II trial is warranted.

Late-stage inhibition of autophagy enhances calreticulin surface exposure.

Calreticulin (CRT) exposure on the cell surface is essential for inducing immunogenic cell death by chemotherapy. Recent studies have shown conflicting effects of chemotherapy-induced autophagy on CRT exposure in cancer cells. Our data revealed that surface-exposed CRT (Ecto-CRT) emission was attenuated by inhibition of autophagy at early stages; however, inhibition of autophagy at late stages resulted in increased Ecto-CRT. Furthermore, neither autophagy activation nor endoplasmic reticulum (ER) stress induction alone was sufficient for CRT surface exposure. Moreover, chemotherapeutic agents that only activated autophagy without inducing ER stress could not increase Ecto-CRT; therefore, combined use of an autophagy activator and ER stress inducer could effectively promote CRT translocation to the plasma membrane. Together, our results highlight the potential of the combined use of ER stress inducers and autophagy late-stage inhibitors to reestablish and strengthen both the CRT exposure and immunogenicity of chemotherapeutic agents induced death cells.

Rejection of adenovirus infection is independent of coxsackie and adenovirus receptor expression in cisplatin-resistant human lung cancer cells.

The adenovirus vector-based cancer gene therapy is controversial. Low transduction efficacy is believed to be one of the main barriers for the decreased expression of coxsackie and adenovirus receptor (CAR) on tumor cells. However, the expression of CAR on primary tumor tissue and tumor tissue survived from treatment has still been not extensively studied. The present study analyzed the adenovirus infection rates and CAR expression in human lung adenocarcinoma cell line A549 and its cisplatin-resistant subline A549/DDP. The results showed that although the CAR expression in A549 and A549/DDP was not different, compared with the A549, A549/DDP appeared obviously to reject adenovirus infection. Moreover, we modified CAR expression in the two cell lines with proteasome inhibitor MG-132 and histone deacetylase inhibitor trichostatin A (TSA), and analyzed the adenovirus infection rates after modifying agent treatments. Both TSA and MG-132 pretreatments could increase the CAR expression in the two cell lines, but the drug pretreatments could only make A549 cells more susceptible to adenovirus infectivity.

Reactive oxygen species mediate oxaliplatin-induced epithelial-mesenchymal transition and invasive potential in colon cancer.

Therapeutic benefits offered by common chemotherapy drugs, such as oxaliplatin, are limited due to the development of resistance, which contributes to treatment failure and metastasis. The epithelial-mesenchymal transition (EMT) is a key event contributing to the development of resistance to chemotherapeutics. Although the relationship between oxaliplatin and chemotherapy resistance has been described for decades, the molecular mechanisms have remained elusive. The aim of the present study was to investigate the underlying mechanisms of oxaliplatin-mediated metastasis. Here, we identify reactive oxygen species (ROS) as mediators that promote the oxaliplatin-induced EMT. Following oxaliplatin treatment, the messenger RNA (mRNA) levels of most peroxiredoxin family genes, except for peroxiredoxin 1 (prdx1) gene, were constant or even decreased, resulting in ROS abundance. And the antioxidant guardian Nrf2 was unconspicuously raised both transcriptionally and translationally with oxaliplatin treatment as compared to those induced by topotecan treatment, which has been proved with no induced metastasis. In addition, the study evaluated high levels of ROS leading to EMT via activation of the known oncogenes Akt and Snail. Using the Akt inhibitor LY294002 or knocking down Snail expression via RNA interference (RNAi) reversed the effects of oxaliplatin on the EMT and metastasis. Our studies establish a role for the ROS-Akt-Snail axis as a mechanism by which chemotherapeutics induce EMT and cancer metastasis.

Efficacy and safety of nab-paclitaxel combined with carboplatin in Chinese patients with melanoma.

This study aimed to evaluate the efficacy and safety of nab-paclitaxel combined with carboplatin in Chinese patients with melanoma. The treatment regimen consisted of nab-paclitaxel (100 mg/m(2)) and carboplatin (area under the curve = 2) administered on days 1 and 8 every 21 days. All of the patients were evaluated on the basis of efficacy and safety in a two-cycle interval. Of the 45 patients, 18 were chemotherapy naive and 27 were chemotherapy treated. Of these cases, 18 manifested acral melanoma and 27 showed non-acral melanomas. Although chemotherapy-naive patients exhibited a higher response to the treatment, similar progression-free survival (PFS) and overall survival (OS) were detected in chemotherapy-naive and chemotherapy-treated patients. A higher response was observed in non-acral melanomas; however, similar PFS and OS occurred between acral and non-acral melanomas. The most common side effects were alopecia, myelosuppression, and gastrointestinal reaction. Nab-paclitaxel combined with carboplatin is a well-tolerated and effective regimen to treat Chinese patients with melanoma, including acral and non-acral melanomas. This treatment may be an alternative approach for Chinese patients with melanoma, especially those without the opportunity to undergo therapy with immune checkpoint inhibitors.

The prognostic value of platelet endothelial cell adhesion molecule-1 in non-small-cell lung cancer patients.

Our previous studies have shown that platelet endothelial cell adhesion molecule-1 (PECAM-1), a member of the immunoglobulin superfamily, is a critical mediator of anchorage-independent growth and anoikis resistance in lung carcinoma cells. The purpose of this study was to analyze the protein expression of PECAM-1 in non-small-cell lung carcinoma (NSCLC) tissues and its clinical significance in NSCLC patients. By immunohistochemical analysis, high microvessel density (MVD) of PECAM-1 was detected in the stromal tissues of NSCLC. The MVD of PECAM-1 was strongly correlated with the N stage (p = 0.029), M stage (p = 0.001) and clinical stage (p = 0.001) of NSCLC patients. Survival analysis revealed high MVD of PECAM-1 in both primary NSCLC lesions and metastatic lymph node tissues, and these results were found to be significantly correlated with poor overall survival in NSCLC patients (p < 0.001 and p = 0.021, respectively). Moreover, patients with high PECAM-1 MVD had worse overall survival in either adenocarcinoma or EGFR mutation subgroups. Multivariate analysis revealed that the MVD of PECAM-1 was an independent prognostic factor for NSCLC patients. The MVD of PECAM-1 is also a potential predictor for NSCLC patients treated with first-line platinum-based doublet chemotherapy, as high PECAM-1 MVD correlated with worse overall survival. Our results demonstrated that MVD of PECAM-1 could be a potential prognostic factor and therapeutic target in NSCLC.

The absence of the ERBB4 hotspot mutations in melanomas in patients from southern China.

V-erb-a erythroblastic leukemia viral oncogene homolog 4 (ERBB4) has been reported to be somatically mutated in 19% of melanoma cases. To investigate the prevalence of ERBB4 mutations in melanoma patients from southern China, we analyzed 117 formalin-fixed, paraffin-embedded melanoma samples archived in the Sun Yat-sen University Cancer Center. A matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platform was used to screen for mutations. No ERBB4 hotspot mutations were detected. Our results indicate that ERBB4 mutations may play a limited role in melanomas in China; therefore, targeting the ERBB4 mutation in melanoma patients from southern China may not be a promising strategy.

A pilot study of paclitaxel combined with gemcitabine followed by interleukin-2 and granulocyte macrophage colony-stimulating factor for patients with metastatic melanoma.

It has been suggested that paclitaxel and gemcitabine modulate the immune system. This paper reports the safety and efficacy of paclitaxel plus gemcitabine followed by interleukin-2 (IL-2)and granulocyte macrophage colony-stimulating factor (GM-CSF), the PGIG chemobiotherapy, for patients with metastatic melanoma. All patients received 175 mg/m ( 2) paclitaxel on day 1 and 800 mg/m ( 2) gemcitabine on day two. IL-2 and GM-CSF were administered from day 4 to day 8 at a dosage of 2 MIU/m ( 2) and 100 µg, respectively. The PGIG chemobiotherapy was repeated every 21 d. Serum cytokine levels at baseline and at the end of the second cycle were measured via flow cytometry. Twenty-seven patients with metastatic melanoma accepted PGIG chemobiotherapy from August 2009 to March 2011. There were five patients that exhibited a partial response, 14 patients that exhibited a stable response and eight that displayed progressive disease. Therefore, the response rate was 18.5%, and the disease control rate was 70.4%. The median time to progression and median survival were 4 mo and 8 mo, respectively. The one-year and two-year survival rates were 25.9% and 18.5%, respectively. Frequent side effects included chills, fever, arthralgia, rash and pruritus. Among the 13 patients who experienced a rash and pruritus and the 14 patients who did not suffer from this side effect, the response rates and disease control rates were 30.8% vs 7.1% and 77% vs 64.2%, respectively. No relationship between serum IL-6 levels, clinical response, and either skin side effect was observed. The PGIG chemobiotherapy is safe and effective for the treatment of patients with advanced melanoma, but randomized trials are necessary to validate this effect.

MicroRNA-214 suppresses growth and invasiveness of cervical cancer cells by targeting UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 7.

MicroRNAs are a class of small noncoding RNAs that function as key regulators of gene expression at the post-transcriptional level. In this study, we demonstrate that miR-214 is frequently down-regulated in cervical cancer, and its expression reduces the proliferation, migration, and invasiveness of cervical cancer cells, whereas inhibiting its expression results in enhanced proliferation, migration, and invasion. miR-214 binds to the 3'-UTR of UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 7 (GALNT7), thereby repressing GALNT7 expression. Furthermore, we are the first to show, using quantitative real-time PCR, that GALNT7 is frequently up-regulated in cervical cancer. The knockdown of GALNT7 markedly inhibits cervical cancer cell proliferation, migration, and invasion, whereas ectopic expression of GALNT7 significantly enhances these properties, indicating that GALNT7 might function as an oncogene in cervical cancer. The restoration of GALNT7 expression can counteract the effect of miR-214 on cell proliferation, migration, and invasiveness of cervical cancer cells. Together, these results indicate that miR-214 is a new regulator of GALNT7, and both miR-214 and GALNT7 play important roles in the pathogenesis of cervical cancer.

Chloroquine enhances the cytotoxicity of topotecan by inhibiting autophagy in lung cancer cells.

Although the anti-malaria drug chloroquine (CQ) has been shown to enhance chemotherapy and radiation sensitivity in clinical trials, the potential mechanisms underlying this enhancement are still unclear. Here, we examined the relevant mechanisms by which the multipotent CQ enhanced the cytotoxicity of topotecan (TPT). The lung cancer cell line A549 was treated with TPT alone or TPT combined with CQ at non-cytotoxic concentrations. Cell viability was assessed using the MTT assay. The percentage of apoptotic cells and the presence of a side population of cells were both determined by flow cytometry. Autophagy and the expression of Bcl-2 family proteins were examined by Western blotting. The accumulation of YFP-LC3 dots and the formation of acidic vesicular organelles were examined by confocal microscopy. CQ sensitized A549 cells to TPT and enhanced TPT-induced apoptosis in a Bcl-2 family protein-independent fashion. CQ inhibited TPT-induced autophagy, which modified the cytotoxicity of TPT. However, CQ failed to modify the transfer of TPT across the cytoplasmic membrane and did not increase lysosomal permeability. This study showed that CQ at non-cytotoxic concentrations potentiated the cytotoxicity of TPT by interfering with autophagy, implying that CQ has significant potential as a chemotherapeutic enhancer.

Mast Cells in Adjacent Normal Colon Mucosa rather than Those in Invasive Margin are Related to Progression of Colon Cancer.

OBJECTIVE: Mast cells (MC) reside in the mucosa of the digestive tract as the first line against bacteria and toxins. Clinical evidence has implied that the infiltration of mast cells in colorectal cancers is related to malignant phenotypes and a poor prognosis. This study compared the role of mast cells in adjacent normal colon mucosa and in the invasive margin during the progression of colon cancer. METHODS: Specimens were obtained from 39 patients with colon adenomas and 155 patients with colon cancers treated at the Sun Yat-sen University Cancer Center between January 1999 and July 2004. The density of mast cells was scored by an immunohistochemical assay. The pattern of mast cell distribution and its relationship with clinicopathologic parameters and 5-year survival were analyzed. RESULTS: The majority of mast cells were located in the adjacent normal colon mucosa, followed by the invasive margin and least in the cancer stroma. Mast cell count in adjacent normal colon mucosa (MCC(adjacent)) was associated with pathologic classification, distant metastases and hepatic metastases, although it was not a prognostic factor. In contrast, mast cell count in the invasive margin (MCC(invasive)) was associated with neither the clinicopathlogic parameters nor overall survival. CONCLUSION: Mast cells in the adjacent normal colon mucosa were related to the progression of colon cancer, suggesting that mast cells might modulate tumor progression via a long-distance mechanism.

Co-expression of nuclear and cytoplasmic HMGB1 is inversely associated with infiltration of CD45RO+ T cells and prognosis in patients with stage IIIB colon cancer.

BACKGROUND: The intratumoral infiltration of T cells, especially memory T cells, is associated with a favorable prognosis in early colorectal cancers. However, the mechanism underlying this process remains elusive. This study examined whether high-mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) molecule, is involved in the infiltration of T cells and disease progression in locally advanced colon cancer. METHODS: Seventy-two cases of pathologically-confirmed specimens were obtained from patients with stage IIIB (T3N1M0) colon cancer who underwent radical resection between January 1999 and May 2002 at the Cancer Center of Sun Yat-Sen University. The density of tumor-infiltrating lymphocytes (TILs) within the tumor tissue and the expression of HMGB1 in the cancer cells were examined via immunohistochemical analysis. The phenotype of CD45RO+ cells was confirmed using a flow cytometric assay. The association between HMGB1 expression, the density of TILs, and the 5-year survival rate were analyzed. RESULTS: The density of CD45RO+ T cells within the tumor was independently prognostic, although a higher density of CD3+ T cells was also associated with a favorable prognosis. More importantly, the expression of HMGB1 was observed in both the nucleus and the cytoplasm (co-expression pattern) in a subset of colon cancer tissues, whereas nuclear-only expression of HMGB1 (nuclear expression pattern) existed in most of the cancer tissues and normal mucosa. The co-expression pattern of HMGB1 in colon cancer cells was inversely associated with the infiltration of both CD3+ and CD45RO+ T cells and 5-year survival rates. CONCLUSIONS: This study revealed that the co-expression of HMGB1 is inversely associated with the infiltration of CD45RO+ T cells and prognosis in patients with stage IIIB colon cancer, indicating that the distribution patterns of HMGB1 might contribute to the progression of colon cancer via modulation of the local immune response.

Expression of calreticulin is associated with infiltration of T-cells in stage IIIB colon cancer.

AIM: To investigate the correlation between expression of calreticulin and infiltration of lymphocytes in stage IIIB colon cancer. METHODS: Sixty-eight pathologically-confirmed specimens were obtained from stage IIIB (T3N1M0) colon cancer patients who underwent radical resection between January 1999 and May 2002 at the Cancer Center of Sun Yat-Sen University, Guangzhou, China. Immunohistochemical analysis was performed to show infiltration of lymphocytes and expression of calreticulin in colon cancer. Association between calreticulin expression, infiltration of lymphocytes, and 5-year survival rate of patients was assessed. RESULTS: The expression level of calreticulin was lower in cancer nest than in its adjacent normal epithelium since 61.8% (42/68) of the samples were stained with calreticulin in colon cancer. The expression of calreticulin in colon cancer was associated with the infiltration of CD45RO+ cells rather than with that of CD3+ cells. In addition, the stronger expression of calreticulin and the higher infiltration of CD3+ and CD45RO+ cells in colon cancer were associated with the higher 5-year survival rate of patients. CONCLUSION: Expression of calreticulin is associated with infiltration of T-cells, which implies that a low expression level of molecular marker may represent a new mechanism underlying immune escape in colon cancer.

The density of macrophages in the invasive front is inversely correlated to liver metastasis in colon cancer.

BACKGROUND: Although an abundance of evidence has indicated that tumor-associated macrophages (TAMs) are associated with a favorable prognosis in patients with colon cancer, it is still unknown how TAMs exert a protective effect. This study examined whether TAMs are involved in hepatic metastasis of colon cancer. MATERIALS AND METHODS: One hundred and sixty cases of pathologically-confirmed specimens were obtained from colon carcinoma patients with TNM stage IIIB and IV between January 1997 and July 2004 at the Cancer Center of Sun Yat-Sen University. The density of macrophages in the invasive front (CD68TFHotspot) was scored with an immunohistochemical assay. The relationship between the CD68TFHotspot and the clinicopathologic parameters, the potential of hepatic metastasis, and the 5-year survival rate were analyzed. RESULTS: TAMs were associated with the incidence of hepatic metastasis and the 5-year survival rate in patients with colon cancers. Both univariate and multivariate analyses revealed that the CD68TFHotspot was independently prognostic of survival. A higher 5-year survival rate among patients with stage IIIB after radical resection occurred in patients with a higher macrophage infiltration in the invasive front (81.0%) than in those with a lower macrophage infiltration (48.6%). Most importantly, the CD68TFHotspot was associated with both the potential of hepatic metastasis and the interval between colon resection and the occurrence of hepatic metastasis. CONCLUSION: This study showed evidence that TAMs infiltrated in the invasive front are associated with improvement in both hepatic metastasis and overall survival in colon cancer, implying that TAMs have protective potential in colon cancers and might serve as a novel therapeutic target.

The overexpression of ERCC-1 is involved in the resistance of lung cancer cells to cetuximab combined with DDP.

Cetuximab, an antibody against epidermal growth factor receptor, has been approved for the treatment of colorectal carcinoma and head and neck squamous cell carcinoma. There is increasing evidence that cetuximab can reverse the resistance to irinotecan (CPT-11) and oxaliplatin. Since cisplatin (DDP) is a widely used chemotherapeutics this study examined whether cetuximab could reverse the resistance to DDP. Combined treatment with DDP and cetuximab resulted in an increase in the cytotoxicity of DDP in a DDP-sensitive lung cancer cell line (A549), but not in a DDP-resistant derivative (A549/DDP). Meantime, DDP activated the EGFR pathway in A549 cells but not in A549/DDP cells in a ligand-independent fashion. After the expression of excision repair cross-complementation group 1 (ERCC-1) protein was inhibited by small interfering RNA (siRNA), the potential of cetuximab to enhance DDP-mediated cytotoxicity was restored in A549/DDP cells. These data suggested that ERCC-1 was involved in the resistance of cetuximab combined with DDP as overexpression of ERCC-1 prohibits the activation of EGFR pathway, which would facilitate the preselection of lung cancer patients for the treatment of cetuximab combined with DDP.

The paradoxical patterns of expression of indoleamine 2,3-dioxygenase in colon cancer.

BACKGROUND: One of the putative mechanisms of tumor immune escape is based on the hypothesis that carcinomas actively create an immunosuppressed state via the expression of indoleamine 2,3-dioxygenase (IDO), both in the cancer cells and in the immune cells among the tumor-draining lymph nodes (TDLN). In an attempt to verify this hypothesis, the patterns of expression of IDO in the cancer cells and the immune cells among colon cancers were examined. METHODS: Seventy-one cases of pathologically-confirmed colon cancer tissues matched with adjacent non-cancerous tissues, lymph node metastases, and TDLN without metastases were collected at the Sun Yat-sen Cancer Center between January 2000 and December 2000. The expression of IDO and Bin1, an IDO regulator, was determined with an immunohistochemical assay. The association between IDO or Bin1 expression and TNM stages and the 5-year survival rate in colon cancer patients was analyzed. RESULTS: IDO and Bin1 were detected in the cytoplasm of cancer cells and normal epithelium. In primary colon cancer, the strong expression of IDO existed in 9/71 cases (12.7%), while the strong expression of Bin1 existed in 33/71 cases (46.5%). However, similar staining of IDO and Bin1 existed in the adjacent non-cancerous tissues. Among the 41 cases with primary colon tumor and lymph node metastases, decreased expression of IDO was documented in the lymph node metastases. Furthermore, among the TDLN without metastases, a higher density of IDO+cells was documented in 21/60 cases (35%). Both univariate and multivariate analyses revealed that the density of IDO+cells in TDLN was an independent prognostic factor. The patients with a higher density of IDO+cells in TDLN had a lower 5-year survival rate (37.5%) than the cells with a lower density (73.1%). CONCLUSION: This study demonstrated paradoxical patterns of expression of IDO in colon cancer. The high density IDO+cells existed in TDLN and IDO was down-regulated in lymph nodes with metastases, implying that IDO in tumor and immune cells functions differently.

Higher percentage of CD133+ cells is associated with poor prognosis in colon carcinoma patients with stage IIIB.

BACKGROUND: Cancer stem cell model suggested that tumor progression is driven by the overpopulation of cancer stem cells and eradicating or inhibiting the symmetric division of cancer stem cells would become the most important therapeutic strategy. However, clinical evidence for this hypothesis is still scarce. To evaluate the overpopulation hypothesis of cancer stem cells the association of percentage of CD133+ tumor cells with clinicopathological parameters in colon cancer was investigated since CD133 is a putative cancer stem cell marker shared by multiple solid tumors. PATIENTS AND METHODS: Tumor tissues matched with adjacent normal tissues were collected from 104 stage IIIB colon cancer patients who were subject to radical resection between January, 1999 to July, 2003 in this center. The CD133 expression was examined with immunohistochemical staining. The correlation of the percentage of CD133+ cell with clinicopathological parameters and patients' 5-year survival was analyzed. RESULTS: The CD133+ cells were infrequent and heterogeneous distribution in the cancer tissue. Staining of CD133 was localized not only on the glandular-luminal surface of cancer cells but also on the invasive budding and the poorly differentiated tumors with ductal structures. Both univariate and multivariate survival analysis revealed that the percentage of CD133+ cancer cells and the invasive depth of tumor were independently prognostic. The patients with a lower percentage of CD133+ cancer cells (less than 5%) were strongly associated with a higher 5-year survival rate than those with a higher percentage of CD133+ cancer cells (greater than or equal to 55%). Additionally, no correlation was obtained between the percentage of CD133+ cancer cells and the other clinicopathological parameters including gender, age, site of primary mass, pathologic types, grades, and invasive depth. CONCLUSION: The fact that a higher percentage CD133+ cells were strongly associated with a poorer prognosis in patients with locally advanced colon cancer implicated that CD133+ cancer cells contribute to the tumor progression, and the overpopulation hypothesis of cancer stem cell seems reasonable.