Treatment strategy for HER2-negative advanced gastric cancer: salvage-line strategy for advanced gastric cancer.

After immune checkpoint inhibitor (ICI) comes into third-line treatment of advanced gastric cancer, the therapeutic strategy has been dramatically changed. Recent first-line regimen, which consists of ICI and chemotherapeutic agents, prolonged progression-free survival, and subsequent treatment options enabled continuous treatment beyond second-line therapy. Moreover, the advent of vascular endothelial growth factor (VEGF)-targeted agents including angiogenesis inhibitors and TKIs provides an opportunity of considering the interaction between ICI and anti-VEGF agents, and facilitating novel treatment proposal. Although clinical benefit of prolonged VEGF blockade after disease progression has not been confirmed in gastric cancer, combination therapy of cytotoxic agents and anti-VEGF agent, such as irinotecan plus ramucirumab demonstrated favorable objective response rate and progression-free survival in third- or later-line setting. In this review, we discuss recent progress and future directions of later-line treatments of HER2-negative advancer gastric cancer.

Specific activation of glycolytic enzyme enolase 2 in BRAF V600E-mutated colorectal cancer.

The BRAF V600E mutation occurs in approximately 10% of patients with metastatic colorectal cancer (CRC) and constitutes a distinct subtype of the disease with extremely poor prognosis. To address this refractory disease, we investigated the unique metabolic gene profile of BRAF V600E-mutated tumors via in silico analysis using a large-scale clinical database. We found that BRAF V600E-mutated tumors exhibited a specific metabolic gene expression signature, including some genes that are associated with poor prognosis in CRC. We discovered that BRAF V600E-mutated tumors expressed high levels of glycolytic enzyme enolase 2 (ENO2), which is mainly expressed in neuronal tissues under physiological conditions. In vitro experiments using CRC cells demonstrated that BRAF V600E-mutated cells exhibited enhanced dependency on ENO2 compared to BRAF wild-type cancer cells and that knockdown of ENO2 led to the inhibition of proliferation and migration of BRAF V600E-mutated cancer cells. Moreover, inhibition of ENO2 resulted in enhanced sensitivity to vemurafenib, a selective inhibitor of BRAF V600E. We identified AP-1 transcription factor subunit (FOSL1) as being involved in the transcription of ENO2 in CRC cells. In addition, both MAPK and PI3K/Akt signaling were suppressed upon inhibition of ENO2, implying an additional oncogenic role of ENO2. These results suggest the crucial role of ENO2 in the progression of BRAF V600E-mutated CRC and indicate the therapeutic implications of targeting this gene.

Impact of sarcopenia in patients with advanced or recurrent colorectal cancer treated with regorafenib.

BACKGROUND: Regorafenib is a key agent for patients with advanced or recurrent colorectal cancer. Sarcopenia represented by skeletal muscle depletion is closely related to frailty and predicts oncological prognoses. We hypothesized that sarcopenia negatively affects the time to treatment failure (TTF) or overall survival (OS) of patients treated with regorafenib. METHODS: We retrospectively reviewed the medical records of all patients treated with regorafenib between May 2013 and April 2019 at our institution. The cross-sectional area of the psoas muscle at the level of the third lumbar vertebra on baseline computed tomography (CT) was assessed to calculate the psoas muscle index (PMI). Sarcopenia was defined based on PMI cut-off values for Asian adults (6.36 cm2/m2 for males and 3.92 cm2/m2 for females). RESULTS: Thirty-four patients were analyzed. The prevalence of sarcopenia was 44.1%. Sarcopenia was significantly associated with poorer OS (median 3.2 vs. 5.3 months, p = 0.031). Less 75% 1-Month Relative Dose Intensity patients experienced significantly shorter TTF and OS than the rest, as did patients receiving total regorafenib dose of < 3360 mg (median 3.1 and 9.4 months, p < 0.001). Multivariate analysis showed that sarcopenia was a significant predictor of prognosis. CONCLUSION: Sarcopenia was a predictive marker of negative outcome for patients with advanced or recurrent colorectal cancer treated with regorafenib. Screening for sarcopenia can be used to identify patients more likely to benefit from regorafenib in routine clinical practice.

Dysphagia Score as a Predictor of Adverse Events Due to Triplet Chemotherapy and Oncological Outcomes in 434 Consecutive Patients with Esophageal Cancer.

BACKGROUND: Dysphagia is a major symptom of esophageal cancer (EC) that significantly affects patient quality of life; however, little is known regarding its clinical impact on the treatment course in patients with EC. METHODS: This retrospective study included 434 consecutive patients with EC who received docetaxel, cisplatin, and 5-fluorouracil (DCF) chemotherapy as an initial treatment. We evaluated the relationships between the dysphagia score at diagnosis and clinicopathological factors, including DCF therapy-related adverse events, tumor response, and survival. RESULTS: The dysphagia scores were 0 in 208 patients (47.9%), 1 in 82 patients (18.9%), 2 in 52 patients (12.0%), 3 in 59 patients (13.6%), and 4 in 33 patients (7.6%). High (≥ 3) dysphagia scores were significantly associated with high incidences of grade 3/4 febrile neutropenia (FN) (79.3 vs. 35.7%, P < 0.001) and diarrhea (63.0 vs. 28.1%, P < 0.001) compared with low (≤ 2) scores. Logistic regression analysis further identified the dysphagia scores as an independent predictor of both FN and severe diarrhea during DCF chemotherapy. Furthermore, compared with low scores, high dysphagia scores were associated with a worse clinical response to chemotherapy (response rate 65.2 vs. 78.7%, P = 0.008) and worse 5-year overall survival (35.4 vs. 56.4%, P = 0.001). CONCLUSIONS: The dysphagia score at diagnosis was an independent predictor of FN and severe diarrhea. Furthermore, this score might be useful in predicting chemotherapy response and long-term survival in patients treated with DCF.

Micro-RNA-130a-3p Regulates Gemcitabine Resistance via PPARG in Cholangiocarcinoma.

BACKGROUND: The prognosis of cholangiocarcinoma (CCA) is so poor that its chemoresistance needs to be reduced. In this study, we focused on the microRNAs (miRNAs) associated with gemcitabine resistance of CCA and assessed the clinical significance of miRNAs and their target genes. METHODS: We performed miRNA microarray analysis for two CCA cell lines (CCLP-1 and MzChA-1) and their gemcitabine-resistant (GR) cells. An miR-130a-3p mimic was induced into CCA cells using lipofection, and we used pioglitazone as a peroxisome proliferator-activated receptor-γ (PPARγ) agonist in vitro. The expression of miR-130a-3p was studied in 27 intrahepatic CCA samples after laser capture microdissection (LCM) and by immunohistochemistry from patients who had undergone curative resection from March 2004 to November 2012 at Osaka University Hospital. RESULTS: miR-130a-3p expression was upregulated in CCLP-1-GRs and MzChA-1-GRs significantly more than in their parental cells. Transfection of the miR-130a-3p mimic into CCA cells increased gemcitabine resistance, and we detected PPARG as a target gene of miR-130a-3p. Furthermore, pioglitazone had a synergistic effect with gemcitabine and alleviated gemcitabine resistance of CCA GR cells. Moreover, clinical examination revealed that for patients who underwent adjuvant gemcitabine therapy, those who were PPARγ positive had significantly longer disease-free survival than those who were PPARγ negative (n = 5 and 11, respectively; p = 0.027). CONCLUSIONS: Our data suggest that miR-130a-3p was associated with gemcitabine resistance in CCA through PPARG, and there is a possibility that pioglitazone can be used for the treatment of CCA.

Clinical Significance of Histone Demethylase NO66 in Invasive Colorectal Cancer.

BACKGROUND: Targeting epigenetic regulators is a promising therapeutic strategy against cancer. However, because of the broad spectrum of targets, selective inhibition of cancer-associated genes remains a major challenge. To address this issue, we focused on the oncogene-regulated histone demethylase, nucleolar protein 66 (NO66 [C14orf169/MAPJD]), which is known to work coordinately with the well-characterized oncogene, c-MYC. METHODS: To investigate expression patterns and clinical significance of NO66 in colorectal cancer (CRC), we performed immunohistochemical staining in 114 CRC cases. We performed functional analysis of NO66 to evaluate its contribution to proliferation and migration ability in CRC cells in vitro. RESULTS: NO66 was selectively expressed in CRC tissues. Furthermore, high expression levels of NO66 were associated with cancer metastatic potential, including lymphatic duct invasion (p = 0.047), venous invasion (p = 0.033), and lymph node metastasis (p = 0.015). Multivariate analysis indicated that NO66 was an independent prognostic factor for overall survival. In vitro assays revealed that NO66 expression is closely associated with malignant potential, including proliferation, migration and anti-apoptotic activity. CONCLUSIONS: NO66 is an independent prognostic factor in CRC. The cancer-selective expression patterns and its involvement in metastatic phenotypes suggest that NO66 is not only a crucial biomarker but is also a promising therapeutic target in CRC.

Role of pyruvate kinase M2 in transcriptional regulation leading to epithelial-mesenchymal transition.

Pyruvate kinase M2 (PKM2) is an alternatively spliced variant of the pyruvate kinase gene that is preferentially expressed during embryonic development and in cancer cells. PKM2 alters the final rate-limiting step of glycolysis, resulting in the cancer-specific Warburg effect (also referred to as aerobic glycolysis). Although previous reports suggest that PKM2 functions in nonmetabolic transcriptional regulation, its significance in cancer biology remains elusive. Here we report that stimulation of epithelial-mesenchymal transition (EMT) results in the nuclear translocation of PKM2 in colon cancer cells, which is pivotal in promoting EMT. Immunoprecipitation and LC-electrospray ionized TOF MS analyses revealed that EMT stimulation causes direct interaction of PKM2 in the nucleus with TGF-ß-induced factor homeobox 2 (TGIF2), a transcriptional cofactor repressor of TGF-ß signaling. The binding of PKM2 with TGIF2 recruits histone deacetylase 3 to the E-cadherin promoter sequence, with subsequent deacetylation of histone H3 and suppression of E-cadherin transcription. This previously unidentified finding of the molecular interaction of PKM2 in the nucleus sheds light on the significance of PKM2 expression in cancer cells.

CCAT2, a novel noncoding RNA mapping to 8q24, underlies metastatic progression and chromosomal instability in colon cancer.

The functional roles of SNPs within the 8q24 gene desert in the cancer phenotype are not yet well understood. Here, we report that CCAT2, a novel long noncoding RNA transcript (lncRNA) encompassing the rs6983267 SNP, is highly overexpressed in microsatellite-stable colorectal cancer and promotes tumor growth, metastasis, and chromosomal instability. We demonstrate that MYC, miR-17-5p, and miR-20a are up-regulated by CCAT2 through TCF7L2-mediated transcriptional regulation. We further identify the physical interaction between CCAT2 and TCF7L2 resulting in an enhancement of WNT signaling activity. We show that CCAT2 is itself a WNT downstream target, which suggests the existence of a feedback loop. Finally, we demonstrate that the SNP status affects CCAT2 expression and the risk allele G produces more CCAT2 transcript. Our results support a new mechanism of MYC and WNT regulation by the novel lncRNA CCAT2 in colorectal cancer pathogenesis, and provide an alternative explanation of the SNP-conferred cancer risk.

Susceptibility of pancreatic cancer stem cells to reprogramming.

Previous reports have indicated that reprogramming technologies may be useful for altering the malignant phenotype of cancer cells. Although somatic stem cells in normal tissues are more sensitive to reprogramming induction than differentiated cells, it remains to be elucidated whether any specific subpopulations are sensitive to reprogramming in heterogeneous tumor tissues. Here we examined the susceptibility of pancreatic cancer stem cells (CSC) and non-CSC to reprogramming. To characterize CSC populations, we focused on c-Met signaling, which has been identified as a marker of CSC in mouse experiments in vivo. Cells that expressed high levels of c-Met showed higher CSC properties, such as tumor-initiating capacity, and resistance to gemcitabine. Real-time reverse transcription-polymerase chain reaction in cells expressing high levels of c-Met revealed endogenous expression of reprogramming factors, such as OCT3/4, SOX2, KLF4 and cMYC. Introduction of these four factors resulted in higher alkaline phosphatase staining in cells with high c-Met expression than in controls. Therefore, the study results demonstrate that cellular reprogramming may be useful for extensive epigenetic modification of malignant features of pancreatic CSC.

Prognostic Impact of Peritumoral IL-17-Positive Cells and IL-17 Axis in Patients with Intrahepatic Cholangiocarcinoma.

BACKGROUND: Development of cancer has been linked to inflammatory cytokines such as interleukin (IL)-6 and IL-17. In this study, we assessed the expression of these cytokines in intrahepatic cholangiocarcinoma (ICC) and determined their correlation to the survival probability. METHODS: A total of 72 consecutive patients who underwent curative resection of ICC at Osaka University Hospital from March 1998 to November 2014 were enrolled. Immunohistochemical analysis was performed for IL-17 and its receptor A (IL-17RA), as well as IL-6. Enzyme-linked immunosorbent assay (ELISA) was performed for preoperative plasma levels of IL-6 and IL-17 in 32 patients with ICC. RESULTS: Immunohistochemical analysis showed that the IL-6(high) (n = 34) and IL-17RA(high) (n = 29) groups had significantly worse disease-free survival (DFS) than IL-6(low) (n = 38) and IL-17RA(low) (n = 43) groups, respectively. Although IL-17(+) cells were abundant in the intratumoral area, patients with high peritumoral, but not intratumoral, IL-17(+) cells (n = 28) corresponded with a significantly lower overall survival (OS) and DFS (OS, p = 0.023; DFS, p = 0.026) than those with low group. Moreover, multivariate Cox proportional hazards analysis revealed that IL-6, peritumoral IL-17(+), and IL-17RA are independent prognostic factors for DFS (p = 0.023, p = 0.0088, p = 0.039, respectively). In addition, high preoperative plasma levels of IL-6 in patients with ICC corresponded with significantly lower DFS (p = 0.002). CONCLUSIONS: Our data suggested that IL-6, peritumoral IL-17(+) cells, and IL-17RA expression are postoperative useful markers for predicting recurrence in patients with ICC.

[Therapeutic Implication Targeting for Cancer Stem Cells].

Cancer has been viewed as a heterogeneous population of cells.While the large majority of cells that constituting tumors are differentiated, and eventually stop dividing, only a minority population of cells, termed cancer stem cells, is capable of unlimited self-renewal and multi-differentiation, just like somatic stem cells in normal tissues.Cancer stem cells have been identified in a variety of cancers of the blood, brain, stomach, colon, and pancreas.In this review we present current evidence supporting the cancer stem cell model of tumor progression, and discuss the experimental and therapeutic implications.

Combined evaluation of hexokinase 2 and phosphorylated pyruvate dehydrogenase-E1α in invasive front lesions of colorectal tumors predicts cancer metabolism and patient prognosis.

Although numerous studies have shown the significance of cancer-specific aerobic glycolysis, how glycolysis contributes to tumor invasion, a critical phenomenon in metastasis, remains unclear. With regard to colorectal cancer (CRC), we studied two critical gate enzymes, hexokinase 2 (HK2), which is involved in glycolysis, and phosphorylated pyruvate dehydrogenase-E1α (p-PDH), which is involved in oxidative phosphorylation (OxPhos). Immunohistochemical analyses using anti-HK2 and p-PDH antibodies were performed on surgically resected CRC samples (n = 104), and the expression in invasive front lesions of tumors was assessed. Positive HK2 expression correlated with extensive tumor diameter (P = 0.0460), advanced tumor depth (P = 0.0395), and presence of lymph node metastasis (P = 0.0409). Expression of p-PDH tended to be higher in right-sided CRCs than in left-sided CRCs (P = 0.0883). In survival analysis, the combined evaluation of positive HK2 and negative p-PDH was associated with reduced recurrence-free survival (RFS) (P = 0.0169 in all stages and P = 0.0238 in Stage II and III patients, respectively). This evaluation could predict RFS more precisely than the independent evaluation. The present study indicated that high HK2 expression combined with low p-PDH expression in the invasive front lesions of CRC tumors is predictive of tumor aggressiveness and survival of CRC cases.

Cancer stem cells of the digestive system.

Stem cells of the digestive system are ideal in many ways for research, given they are abundant, highly proliferative and have a uniform structural arrangement. This in turn has enormously aided the research of cancer stem cells of the digestive system, which is now shaping our understanding of cancer stem cells. In this review, the recent advances in the understanding of cancer stem cells of the digestive system have been summarized, including aspects such as their identification, origin, cell-cycle dormancy, relationship with epithelial-mesenchymal transition, cellular metabolism and the underlying molecular mechanisms. Newly acquired knowledge concerning cancer stem cells have led to the development of novel cancer therapeutics with provisional yet encouraging results.

Dabrafenib and trametinib administration in patients with BRAF V600E/R or non-V600 BRAF mutated advanced solid tumours (BELIEVE, NCCH1901): a multicentre, open-label, and single-arm phase II trial.

Background: BRAF V600 mutations are common in melanoma, thyroid, and non-small-cell lung cancers. Despite dabrafenib and trametinib being standard treatments for certain cancers, their efficacy across various solid tumours remains unelucidated. The BELIEVE trial assessed the efficacy of dabrafenib and trametinib in solid tumours with BRAF V600E/R or non-V600 BRAF mutations. Methods: Between October 1, 2019, and June 2022, at least 50 patients with measurable and seven without measurable diseases examined were enrolled in a subcohort of the BELIEVE trial (NCCH1901, jRCTs031190104). BRAF mutated solid tumour cases other than BRAF V600E mutated colorectal cancer, melanoma, and non-small cell lung cancer cases were included. Patients with solid tumours received dabrafenib (150 mg) twice daily and trametinib (2 mg) once daily until disease progression or intolerable toxicity was observed. The primary endpoint was overall response rate (ORR), and secondary endpoints included progression-free survival (PFS), 6-month PFS, and overall survival (OS). Bayesian analysis was performed using a prior distribution with a 30% expected response rate [Beta (0.6, 1.4)]. Findings: Fourty-seven patients with measurable disease, mainly with the BRAF V600E mutation (94%), and three others with non-V600E BRAF mutations (V600R, G466A, and N486_P490del) were enrolled. The primary sites included the thyroid gland, central nervous system, liver, bile ducts, colorectum, and pancreas. The confirmed ORR was 28.0%; the expected value of posterior distribution [Beta (14.6, 37.4)] was 28.1%, although the primary endpoint was achieved, not exceeding an unexpectedly high response rate of 60% obtained using Bayesian analysis. The disease control rate (DCR) was 84.0%. The median PFS was 6.5 months (95% confidence interval [CI]; 4.2-7.2 months, 87.8% at 6 months). Responses were observed across seven tumour types. Median OS was 9.7 months (95% CI, 7.5-12.2 months). Additional patients without measurable diseases had a median PFS of 4.5 months. Adverse events (AEs) were consistent with previous reports, with 45.6% of patients experiencing grade ≥3 AEs. Interpretation: This study reported promising efficacy against BRAF V600-mutant tumours. Dabrafenib and trametinib would offer a new therapeutic option for rare cancers, such as high-grade gliomas, biliary tract cancer, and thyroid cancer. Funding: This study was funded by the Japan Agency for Medical Research and Development (22ck0106622h0003) and a Health and Labour Sciences Research Grant (19EA1008).

Expression of mesenchymal markers vimentin and fibronectin: the clinical significance in esophageal squamous cell carcinoma.

BACKGROUND: The importance of mesenchymal characteristics has not been fully elucidated in esophageal cancer. METHODS: Ten normal and 77 tumor specimens were collected. Microarray analysis was performed to analyze the expression patterns of epithelial markers, mesenchymal markers, epithelial mesenchymal transition (EMT)-related genes and stem cell markers. RT-PCR analysis was conducted to confirm the results of microarray analysis. Immunohistochemical analysis was performed to verify the level of protein expression. Statistical analysis was performed to investigate the correlation between selected genes and clinicopathological factors. RESULTS: Microarray analysis showed that epithelial markers were significantly down-regulated whereas mesenchymal markers and EMT transcription factors were up-regulated in cancer cells. Two types of gene expression patterns were found in the clustering analysis, type 1 tumors and type 2 tumors. Type 1 tumor clusters did not reveal a fixed gene expression pattern whereas type 2 tumor clusters revealed up-regulation of mesenchymal markers EMT inducers and related genes. Vimentin and fibronectin were selected to distinguish between tumor types 1 and 2. Type 2 tumors showed significantly larger tumor sizes (p < 0.0001), wider ranges of lymph node metastasis (p = 0.0057), and a more severe clinical stage (p < 0.0001) than did type 1 tumors. The prognosis of patients with type 2 tumors was significantly worse than that of patients with type 1 tumors. Univariate and multivariate analyses revealed that classification of type 2 tumors was an independent prognostic factor. CONCLUSIONS: The analysis of mesenchymal markers in esophageal cancer is useful in distinguishing patients with a poor prognosis.

Long noncoding RNA 01534 maintains cancer stemness by downregulating endoplasmic reticulum stress response in colorectal cancer.

Background: Studies have shown that cancer stemness and the endoplasmic reticulum (ER) stress response are inversely regulated in colorectal cancer (CRC), but the mechanism has not been fully clarified. Long noncoding RNAs (lncRNAs) play key roles in cancer progression and metastasis. In this study we investigated lncRNA 01534 (LINC01534) as a possible modulator between cancer stemness and ER stress response. Methods: In vitro experiments using CRC cell lines were performed to explore a possible role of LINC01534. The expression of LINC01534 in clinical CRC samples was assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and in situ hybridization. Results: Silencing LINC01534 led to suppression of cell proliferation, invasiveness, and cell cycle progression at the G2-M phase, and promoted apoptosis. Moreover, we found that silencing LINC01534 suppressed cancer stemness, while it activated the ER stress response, especially through the PERK/eIF2α signaling pathway. In situ hybridization revealed LINC01534 was expressed in tumor cells and upregulated in CRC tissues compared with normal epithelium. A survival survey indicated that high LINC01534 expression was significantly associated with shorter overall survival in 187 CRC patients. Conclusion: This is the first report on LINC01534 in human cancer. Our findings suggest that LINC01534 may be an important modulator of the maintenance of cancer stemness and suppression of the ER stress response, and that it could be a novel prognostic factor in CRC.

Clinical outcomes of neoadjuvant chemotherapy for resectable colorectal liver metastasis with intermediate risk of postoperative recurrence: A multi-institutional retrospective study.

Aims: Risk-scoring systems for colorectal liver metastasis (CRLM) after hepatectomy allow prognoses to be predicted preoperatively. We investigated the clinical outcomes of neoadjuvant chemotherapy for resectable CRLM according to patient risk status, aiming to determine the subgroup of patients who could benefit from neoadjuvant chemotherapy. Methods: In this multi-institutional retrospective analysis, the preoperative risk score was calculated from six previously reported factors: synchronous metastases, primary lymph node positivity, tumor number, largest tumor diameter, extrahepatic metastasis, and the preoperative carbohydrate antigen 19-9 level. Patients were divided into three groups according to their risk scores: low risk (score = 0), intermediate risk (score 1-10), and high risk (score ≥11). Overall and recurrence-free survival curves were calculated using the Kaplan-Meier method. After propensity-score matching in the intermediate-risk group, we compared clinicopathological features and outcomes. Results: There were 318 cases, from 20 institutions. The preoperative risk score could be calculated in 277 cases. There were 34, 192, and 51 patients in the low-, intermediate-, and high-risk groups, respectively. Intermediate-risk group patients who received neoadjuvant chemotherapy had significantly better recurrence-free survival than that of patients without neoadjuvant chemotherapy (P = .0453). After propensity-score matching in the intermediate-risk group, the recurrence-free survival rate was better in patients who received neoadjuvant chemotherapy (P = .0261). But the overall survival rate was not improved after the matching. Conclusion: Neoadjuvant chemotherapy for resectable CRLM might prolong the recurrence-free survival period for intermediate-risk patients with preoperative risk scores in the range of 1-10, but the overall survival was not improved by neoadjuvant chemotherapy.

Early detection of brain metastases and appropriate local therapy followed by systemic chemotherapy may improve the prognosis of gastric cancer.

Brain metastases develop in 0.5-0.7% of patients with gastric/gastroesophageal junction (G/GEJ) cancer. Although rare, brain metastasis is often identified when the patient is already symptomatic; hence prognosis is poor. Given the therapeutic developments for G/GEJ cancer, overall survival is prolonged, thereby the incidence of brain metastases is predicted to increase. We retrospectively surveyed the rate of brain metastasis among 1257 patients diagnosed with G/GEJ cancer who received chemotherapy between January 2011 and April 2021. We investigated the time of onset of brain metastasis, treatments administered, and impact of the metastasis on the overall treatment course and prognosis. Of the 741 patients included in the analysis, brain metastasis was confirmed in 16 (2.2%). The median survival time (MST) from G/GEJ cancer diagnosis was 14.9 months in patients with brain metastasis detected during the treatment period, and the MST from the diagnosis of brain metastasis was 2.8 months. Patients who received chemotherapy exhibited prolonged survival compared with those who did not (12.4 months vs 1.0 months, p < 0.001). Our findings suggest that the early detection of brain metastases and local therapy for poor responders to chemotherapy enable the continuation of chemotherapy and prolong survival.

Downregulation of miR-144 is associated with colorectal cancer progression via activation of mTOR signaling pathway.

The mammalian target of rapamycin (mTOR) is a downstream integrator of essential pathways. mTOR signaling is frequently dysregulated in a variety of human cancers, and in silico analysis has revealed two miR-144 binding sites in the mTOR 3' untranslated region. We investigated the clinicopathologic magnitude of the mTOR pathway regulating microRNA, miR-144 in colorectal cancer (CRC) cases. The regulation of mTOR by miR-144 was examined with inhibitor miR-144-transfected cells. We also investigated changes in sensitivity to the mTOR inhibitor, rapamycin, in inhibitor miR-144-transfected cells. Quantitative RT-PCR was used to evaluate the clinicopathologic significance of miR-144 expression in 137 CRC. Furthermore, we assessed the correlation between CRC prognosis and the expression of 16 genes in the Akt/mTOR pathway. In vitro assays showed that mTOR is a direct target of miR-144, and downregulation of miR-144 facilitated proliferation of CRC cell line, HT29. In addition, the viability of HT29 cells with downregulated miR-144 expression was significantly reduced with rapamycin treatment. Low expression levels of miR-144 were associated with enhanced malignant potential such as venous invasion (P = 0.0013), liver metastasis (P = 0.08), liver recurrence (P = 0.0058) and poor prognosis (P = 0.0041). Multivariate analysis indicated that low miR-144 expression was an independent prognostic factor for survival. Among many genes consisting of the mTOR pathway, only high expression of Rictor was associated with poor prognosis of CRC. miR-144 is a meaningful prognostic marker. Downregulation of miR-144 leads to poor prognosis of CRC patients via activation of the mTOR signaling pathway.

MicroRNA-10b is a prognostic indicator in colorectal cancer and confers resistance to the chemotherapeutic agent 5-fluorouracil in colorectal cancer cells.

PURPOSE: Recent evidence has shown that altered patterns of microRNA (miRNA) expression correlate with various human cancers. We investigated the clinical significance of miR-10b and its involvement in chemotherapeutic resistance to 5-fluorouracil (5-FU), which is a key component of common chemotherapy regimens in colorectal cancer. METHODS: Quantitative RT-PCR was used to evaluate the clinicopathologic significance of miR-10b expression in 88 colorectal cancer cases. We also investigated the chemotherapeutic sensitivity to 5-FU in miR-10b-overexpressing colorectal cancer cells. To explore the mechanism of chemoresistance in miR-10b transfected cells, we examined whether miR-10b inhibits the pro-apoptotic BH3-only Bcl-2 family member BIM(BCL2L11), a key mediator of chemotherapy-induced cell death. RESULTS: High level miR-10b expression was found to be significantly associated with high incidence of lymphatic invasion (P = 0.0257) and poor prognosis (P = 0.0057). Multivariate analysis indicated that high miR-10b expression is an independent prognostic factor for survival. In vitro studies revealed that miR-10b directly inhibits pro-apoptotic BIM, and the overexpression of miR-10b confers chemoresistance in colorectal cancer cells to 5-FU. CONCLUSIONS: MiR-10b is a novel prognostic marker in colorectal cancer. Moreover, the expression of miR-10b is a potential indicator of chemosensitivity to the common 5-FU-based chemotherapy regimen.