Gastric cancer (GC) is one of the most common malignancies worldwide. Recently, cancer stem cells (CSCs) in tumors were found to possess the ability to sustain tumor self-renewal, initiate tumor progression, and possibly also contribute to cancer metastasis. We immunohistochemically examined expression and distribution of representative CSC markers ALDH1, CD44, and CD133 in primary tumors and lymph node metastasis of GC. Among 190 GC primary tumors, 104 (55%) were positive for ALDH1, 117 (62%) were positive for CD44, and 18 (9%) were positive for CD133. Expression of these three CSC markers was significantly associated with advanced clinicopathologic factors. Patients with CD44- and CD133-positive GC had a poorer survival rate than patients with CD44- and CD133-negative GC (CD44: P < 0.001, CD133: P= 0.006). Univariate and multivariate Cox proportional hazards analysis revealed tumor node metastasis stage, CD44 expression, and CD133 expression to be independent predictors of survival in patients with GC. Comparison of CSC markers in primary and metastatic sites showed ALDH1 positivity to be significantly higher in diffuse-type lymph node metastasis than in the primary tumor (P < 0.001). These results indicate that these CSC markers are important in tumor invasion and metastasis and may be good markers indicating long-term survival in patients with GC.

Mutations in TGFBR2, a component of the transforming growth factor (TGF)-β signaling pathway, occur in high-frequency microsatellite instability (MSI-H) colorectal cancer (CRC). In mouse models, Tgfbr2 inactivation in the intestinal epithelium accelerates the development of malignant intestinal tumors in combination with disruption of the Wnt-β-catenin pathway. However, no studies have further identified the genes influenced by TGFBR2 inactivation following disruption of the Wnt-β-catenin pathway. We previously described CDX2P-G19Cre;Apcflox/flox mice, which is stochastically null for Apc in the colon epithelium. In this study, we generated CDX2P-G19Cre;Apcflox/flox;Tgfbr2flox/flox mice, with simultaneous loss of Apc and Tgfbr2. These mice developed tumors, including adenocarcinoma in the proximal colon. We compared gene expression profiles between tumors of the two types of mice using microarray analysis. Our results showed that the expression of the murine homolog of GSDMC was significantly upregulated by 9.25-fold in tumors of CDX2P-G19Cre;Apcflox/flox;Tgfbr2flox/flox mice compared with those of CDX2P-G19Cre;Apcflox/flox mice. We then investigated the role of GSDMC in regulating CRC tumorigenesis. The silencing of GSDMC led to a significant reduction in the proliferation and tumorigenesis of CRC cell lines, whereas the overexpression of GSDMC enhanced cell proliferation. These results suggested that GSDMC functioned as an oncogene, promoting cell proliferation in colorectal carcinogenesis. In conclusion, combined inactivation of both Apc and Tgfbr2 in the colon epithelium of a CRC mouse model promoted development of adenocarcinoma in the proximal colon. Moreover, GSDMC was upregulated by TGFBR2 mutation in CRC and promoted tumor cell proliferation in CRC carcinogenesis, suggesting that GSDMC may be a promising therapeutic target.

Gastric cancer (GC) is 1 of the most common human cancers. Early detection remains the most promising approach to improving long‐term survival of patients with GC. We previously performed Serial Analysis of Gene Expression (SAGE) on 4 primary GCs and identified several GC‐specific genes including Reg IV. Of these genes, olfactomedin 4 (OLFM4, also known as GW112 or hGC‐1) is a candidate gene for cancer‐specific expression. In this study, we examined the expression of olfactomedin 4 in human GC by immunohistochemistry. We also assessed serum olfactomedin 4 levels in GC patients by enzyme‐linked immunosorbent assay. 94 (56%) of 167 GC cases were positive for olfactomedin 4 by immunostaining. Olfactomedin 4 staining was observed more frequently in stage I/II cases than in stage III/IV cases. The serum olfactomedin 4 concentration in presurgical GC patients (n = 123, mean ± SE, 36.3 ± 3.5 ng/mL) was significantly higher than that in healthy individuals (n = 76, 16.6 ± 1.6 ng/mL). In patients with stage I GC, the sensitivity of serum olfactomedin 4 (25%) and Reg IV (35%) was superior to that of CA19‐9 (5%) or CEA (3%). Furthermore, in patients with stage I GC, the combination of olfactomedin 4 and Reg IV elevated the diagnostic sensitivity to 52%. These results suggest that serum olfactomedin 4 is a useful marker for GC and its measurement alone or in combination with Reg IV has utility in the early detection of GC. © 2009 UICC

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We generated transgenic mice in which human CDX2 gene elements control expression of a tamoxifen-regulated Cre protein (CDX2P-CreER(T2)) to allow for inducible gene targeting in intestinal epithelium. After tamoxifen dosing of CDX2P-CreER(T2) mice, Cre activity was detected in the distal ileal, cecal, colonic, and rectal epithelium, with selected crypt base, transit amplifying, and surface cells all capable of activating Cre function. Four weeks after tamoxifen dosing of CDX2P-CreER(T2) mice carrying a Cre-activated fluorescent reporter, single crypts were uniformly fluorescence positive or negative, reflecting Cre activation in crypt stem cells. Biallelic inactivation of the Apc tumor suppressor gene via the CDX2P-CreER(T2) transgene in colon epithelium led to acute alterations in cell proliferation, apoptosis, and morphology, along with mitotic spindle misorientation, β-catenin nuclear localization, and induction of the intestinal stem cell markers Lgr5 and Musashi-1 and the Sox9 transcription factor. Normal mouse colon epithelium lacks Paneth cells, a key small intestine niche cell type, and Paneth cell differentiation is dependent on Sox9 function. In Apc-deficient colon epithelium, ectopic Paneth-like cells were seen outside the crypt base, such as new crypt budding sites. Our data indicate Apc inactivation via CDX2P-CreER(T2) targeting in mouse colon epithelium is sufficient to induce adenomatous changes and the generation of Paneth-like cells from neoplastic progenitors, with potentially significant roles in colon adenoma development and progression.

Objective: Regenerating islet-derived family, member 4 (regenerating gene type IV, Reg IV) is overexpressed in colorectal cancer (CRC). The aim of this study was to investigate the diagnostic utility of Reg IV determination in sera from patients with CRC. Methods: We examined the expression and distribution of Reg IV in CRC by immunohistochemistry and determined Reg IV levels in sera from patients with CRC by enzyme-linked immunosorbent assay. Results: Immunostaining revealed that 23 of 80 (29%) CRC cases were positive for Reg IV. CRC cases with metastatic recurrence in the liver showed more frequently Reg IV staining than those without (p = 0.0102). Patients with CRC showing Reg IV staining had a significantly worse survival than those without Reg IV staining (p = 0.0117). Preoperatively, serum Reg IV concentrations were not elevated in CRC patients at stage 0–III, being in contrast to the significantly increased preoperative levels in stage IV CRC patients with liver metastasis. Conclusion: These results suggest that Reg IV is a prognosticator for poor survival. Serum Reg IV concentration may predict CRC recurrence in the liver.

While 20–30% of colorectal cancers (CRCs) may arise from precursors with serrated glands, only 8–10% of CRCs manifest serrated morphology at diagnosis. Markers for distinguishing CRCs arising from ‘serrated’ versus ‘conventional adenoma’ precursors are lacking. We studied 36 human serrated CRCs and found CDX2 loss or BRAF mutations in ~60% of cases and often together (p=0.04). CDX2Null/BRAFV600E expression in adult mouse intestinal epithelium led to serrated morphology tumors (including carcinomas) and BRAFV600E potently interacted with CDX2 silencing to alter gene expression. Like human serrated lesions, CDX2Null/BRAFV600E-mutant epithelium expressed gastric markers. Organoids from CDX2Null/BRAFV600E–mutant colon epithelium showed serrated features, and partially recapitulated the gene expression pattern in mouse colon tissues. We present a novel mouse tumor model based on signature defects seen in many human serrated CRCs – CDX2 loss and BRAFV600E. The mouse intestinal tumors show significant phenotypic similarities to human serrated CRCs and inform about serrated CRC pathogenesis.DOI: http://dx.doi.org/10.7554/eLife.20331.001

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