let-7e downregulation characterizes early phase colonic adenoma in APCMin/+ mice and human FAP subjects.

The crypt-villus axis represents the essential unit of the small intestine, which integrity and functions are fundamental to assure tissue and whole-body homeostasis. Disruption of pathways regulating the fine balance between proliferation and differentiation results in diseases development. Nowadays, it is well established that microRNAs (miRNAs) play a crucial role in the homeostasis maintenance and perturbation of their levels may promote tumor development. Here, by using microarray technology, we analysed the miRNAs differentially expressed between the crypt and the villus in mice ileum. The emerged miRNAs were further validated by Real Time qPCR in mouse model (ApcMin/+), human cell lines and human tissue samples (FAP) of colorectal cancer (CRC). Our results indicated that miRNAs more expressed in the villi compartment are negatively regulated in tumor specimens, thus suggesting a close association between these microRNAs and the differentiation process. Particularly, from our analysis let-7e appeared to be a promising target for possible future therapies and a valuable marker for tumor staging, being upregulated in differentiated cells and downregulated in early-stage colonic adenoma samples.

Gastric and duodenal polyps in familial adenomatous polyposis patients: Conventional endoscopy vs virtual chromoendoscopy (fujinon intelligent color enhancement) in dysplasia evaluation.

AIM: To test the fujinon intelligent color enhancement (FICE) in identifying dysplastic or adenomatous polyps in familial adenomatous polyposis (FAP) patients. METHODS: Seventy-six consecutive FAP patients, already treated by colectomy and members of sixty-five families, were enrolled. A FICE system for the upper gastro-intestinal tract with an electronic endoscope system and a standard duodenoscope (for side-viewing examination) were used by two expert examiners. Endoscopic resection was performed with diathermic loop for polyps ≥ 6 mm and with forceps for polyps < 6 mm. Formalin-fixed biopsy specimens were analyzed by two expert gastrointestinal pathologists blinded to size, location and number of FAP-associated fundic gland polyps. RESULTS: Sixty-nine (90.8%) patients had gastric polyps (34 only in the corpus-fundus, 7 only in the antrum and 28 in the whole stomach) and 52 (68.4%) in duodenum (7 in the bulb, 35 in second/third duodenal portion, 10 both in the bulb and the second portion of duodenum). In the stomach fundus after FICE evaluation, 10 more polyps were removed from 10 patients for suspicious features of dysplasia or adenomas, but they were classified as cystic fundic gland after histology. In the antrum FICE identified more polyps than traditional endoscopy, showing a better tendency to identify adenomas and displastic areas. In the duodenum FICE added a significant advantage in identifying adenomas in the bulb and identified more polyps in the II/III portion. CONCLUSION: FICE significantly increases adenoma detection rate in FAP patients but does not change any Spigelman stage and thus does not modify patient's prognosis and treatment strategies.

Correlation between mutations and mRNA expression of APC and MUTYH genes: new insight into hereditary colorectal polyposis predisposition.

BACKGROUND: Transcript dosage imbalance may influence the transcriptome. To gain insight into the role of altered gene expression in hereditary colorectal polyposis predisposition, in the present study we analyzed absolute and allele-specific expression (ASE) of adenomatous polyposis coli (APC) and mutY Homolog (MUTYH) genes. METHODS: We analyzed DNA and RNA extracted from peripheral blood mononuclear cells (PBMC) of 49 familial polyposis patients and 42 healthy blood donors selected according similar gender and age. Patients were studied for germline alterations in both genes using dHPLC, MLPA and automated sequencing. APC and MUTYH mRNA expression levels were investigated by quantitative Real-Time PCR (qRT-PCR) analysis using TaqMan assay and by ASE assays using dHPLC-based primer extension. RESULTS: Twenty out of 49 patients showed germline mutations: 14 in APC gene and six in MUTYH gene. Twenty-nine patients did not show mutations in both genes. Results from qRT-PCR indicated that gene expression of both APC and MUTYH was reduced in patients analyzed. In particular, a significant reduction in APC expression was observed in patients without APC germline mutation vs control group (P < 0.05) while APC expression in the mutation carrier patients, although lower compared to control individuals, did not show statistical significance. On the other hand a significant reduced MUTYH expression was detected in patients with MUTYH mutations vs control group (P < 0.05). Altered ASE of APC was detected in four out of eight APC mutation carriers. In particular one case showed a complete loss of one allele. Among APC mutation negative cases, 4 out of 13 showed a moderate ASE. ASE of MUTYH did not show any altered expression in the cases analyzed. Spearman's Rho Test analysis showed a positive and significant correlation between APC and MUTYH genes both in cases and in controls (P = 0.020 and P < 0.001). CONCLUSIONS: APC and MUTYH showed a reduced germline expression, not always corresponding to gene mutation. Expression of APC is decreased in mutation negative cases and this appears to be a promising indicator of FAP predisposition, while for MUTYH gene, mutation is associated to reduced mRNA expression. This study could improve the predictive genetic diagnosis of at-risk individuals belonging to families with reduced mRNA expression regardless of presence of mutation.

The insulin receptor substrate 1 (IRS1) in intestinal epithelial differentiation and in colorectal cancer.

Colorectal cancer (CRC) is associated with lifestyle factors that affect insulin/IGF signaling, of which the insulin receptor substrate 1 (IRS1) is a key transducer. We investigated expression, localization and pathologic correlations of IRS1 in cancer-uninvolved colonic epithelium, primary CRCs with paired liver metastases and in vitro polarizing Caco2 and HT29 cells. IRS1 mRNA and protein resulted higher, relative to paired mucosa, in adenomas of familial adenomatous polyposis patients and in CRCs that overexpressed c-MYC, ß-catenin, InsRß, and IGF1R. Analysis of IRS1 immunostaining in 24 cases of primary CRC with paired colonic epithelium and hepatic metastasis showed that staining intensity was significantly higher in metastases relative to both primary CRC (P<0.01) and colonic epithelium (P<0.01). Primary and metastatic CRCs, compared to colonic epithelium, contained significantly higher numbers of IRS1-positive cells (P = 0.013 and P = 0.014, respectively). Pathologic correlations in 163 primary CRCs revealed that diffuse IRS1 staining was associated with tumors combining differentiated phenotype and aggressive markers (high Ki67, p53, and ß-catenin). In Caco 2 IRS1 and InsR were maximally expressed after polarization, while IGF1R was highest in pre-polarized cells. No nuclear IRS1 was detected, while, with polarization, phosphorylated IRS1 (pIRS1) shifted from the lateral to the apical plasma membrane and was expressed in surface cells only. In HT29, that carry mutations constitutively activating survival signaling, IRS1 and IGF1R decreased with polarization, while pIRS1 localized in nuclear spots throughout the course. Overall, these data provide evidence that IRS1 is modulated according to CRC differentiation, and support a role of IRS1 in CRC progression and liver metastatization.

Ileal pouch adenomas and carcinomas after restorative proctocolectomy for familial adenomatous polyposis.

BACKGROUND: Restorative proctocolectomy and IPAA has become the treatment of choice in familial adenomatous polyposis. However, several cases of adenomas and carcinomas arising in the ileal pouch were reported. OBJECTIVE: The aim of this study was to evaluate the prevalence and natural history of ileal pouch adenomas and the development of carcinomas in patients with restorative proctocolectomy for familial adenomatous polyposis. DESIGN AND SETTING: We prospectively studied patients who underwent IPAA during the past 20 years at the surgical unit of the University of Florence in Italy. MAIN OUTCOME MEASURES: We investigated the extent of the risk and the factors that are involved in the development of neoplastic changes of the pouch. Furthermore, because it is not entirely clear when and how polyps should be treated, we have revised our modality of treatment for this unusual pathology. PATIENTS: Sixty-nine patients with familial adenomatous polyposis underwent restorative proctocolectomy. In 66 patients, handsewn ileoanal anastomosis with anal canal mucosectomy was performed. After surgery, all patients underwent endoscopic surveillance. RESULTS: After 10 years of follow-up, 1 ileal pouch adenoma was found in 64.9% of restorative proctocolectomy patients, and ileal pouch carcinomas occurred in 2 patients (29 and 59 years old), 3 and 11 years after restorative proctocolectomy. The number of colonic adenomatous polyps influenced the occurrence of pouch adenomas. No patients with <200 colonic adenomas experienced pouch adenomas, but 46% of patients with >1000 colonic polyps had pouch adenomas, and 25% of patients with 200 to 1000 colonic polyps had pouch adenomas at follow-up. No relationship was found between ileal pouch adenomas and pouch shape (J, S, or straight ileoanal anastomosis with multiple myotomies) or the APC mutation. Polyps larger than 5 mm were removed by endoscopy or surgery. CONCLUSIONS: Ileal pouch adenomas were common after restorative proctocolectomy. Patients >50 years of age and patients with >1000 colonic adenomas at the time of colectomy were more prone to ileal pouch adenomas. The development of malignancy in the terminal ileum can present a fast course and does not seem to follow the classic adenoma-carcinoma sequence.

High resolution melting analysis for a rapid identification of heterozygous and homozygous sequence changes in the MUTYH gene.

BACKGROUND: MUTYH-associated polyposis (MAP) is an autosomal recessive form of intestinal polyposis predisposing to colorectal carcinoma. High resolution melting analysis (HRMA) is a mutation scanning method that allows detection of heterozygous sequence changes with high sensitivity, whereas homozygosity for a nucleotide change may not lead to significant curve shape or melting temperature changes compared to homozygous wild-type samples. Therefore, HRMA has been mainly applied to the detection of mutations associated with autosomal dominant or X-linked disorders, while applications to autosomal recessive conditions are less common. METHODS: MUTYH coding sequence and UTRs were analyzed by both HRMA and sequencing on 88 leukocyte genomic DNA samples. Twenty-six samples were also examined by SSCP. Experiments were performed both with and without mixing the test samples with wild-type DNA. RESULTS: The results show that all MUTYH sequence variations, including G > C and A > T homozygous changes, can be reliably identified by HRMA when a condition of artificial heterozygosity is created by mixing test and reference DNA. HRMA had a sensitivity comparable to sequencing and higher than SSCP. CONCLUSIONS: The availability of a rapid and inexpensive method for the identification of MUTYH sequence variants is relevant for the diagnosis of colorectal cancer susceptibility, since the MAP phenotype is highly variable.

Thymidylate synthase expression and genotype have no major impact on the clinical outcome of colorectal cancer patients treated with 5-fluorouracil.

BACKGROUND AND OBJECTIVES: Thymidylate synthase (TS) expression levels appear to be related to response to 5-fluorouracil-(5-FU)-based chemotherapy in colorectal cancer (CRC) patients. Three polymorphisms have been proposed as modulators of TS expression: a tandemly repeated sequence (2R/3R) in the 5' UTR, a SNP (G>C) within the 3R allele and a 6bp deletion in the 3' UTR. To evaluate the influence of TS expression and polymorphisms on clinical outcome of 5-FU-treated patients we performed a comprehensive genetic analysis on 63 CRC patients. METHODS: TS expression levels were analyzed in normal and tumor tissues. TS coding sequence and UTR polymorphisms were investigated on DNA from normal tissue. LOH analysis was performed to determine tumor genotype. RESULTS: A difference in disease-free survival (DFS), although not statistically significant, was observed between high and low mRNA expression levels: patients with low levels showed longer DFS. The 2R2R genotype showed significantly lower expression than the 3R3R and 2R3R genotypes in normal tissue. No other TS polymorphism was associated with mRNA expression or clinical outcome. CONCLUSIONS: The results obtained in this pilot study indicate that the number of 5' UTR repeats is the major genetic determinant of TS expression. The lack of association with other polymorphisms might be partially explained by the existence of linkage disequilibrium in the TS gene. Our data support the growing evidence that TS control may require multiple mechanisms acting in close coordination with one another and suggest that TS genotyping alone in tumor samples is not sufficient to accurately predict response to 5-FU.

Identification of potential pharmacogenomic markers of clinical efficacy of 5-fluorouracil in colorectal cancer.

Although adjuvant chemotherapy has significantly increased overall survival in resected Stage III colorectal cancer, disease recurrence is still high (30-40%). 20-25% of Stage II patients also develop recurrent disease. Thus, high-risk patients may benefit from chemotherapy. As patient response to standard chemotherapy varies, the study of molecular differences in the expression of pharmacologically relevant genes may help clinicians to understand variability and tailor therapy. The expression of 5-fluorouracil (5-FU) pathway genes in tumors from 53 Stages II-III colorectal cancer patients who underwent 5-FU adjuvant chemotherapy was investigated by reverse transcription quantitative real-time polymerase chain reaction. Patients were dichotomized into high- and low-mRNA expression level groups using median values of gene mRNA levels. Then, a threshold analysis to identify a cut-off distinguishing recurrent- or nonrecurrent-disease was used. A high degree of interpatient variation in relative tumor expression of study genes was observed. Multiple gene correlations were found, which suggest possible coregulation mechanisms. No statistically significant relationship between experimental data and baseline clinical/pathological characteristics or clinical outcome was observed using gene expression median values. Threshold analysis indicated significant inverse relationships between deoxyuridine triphosphatase (DUT), ferrodoxin reductase (FDXR) or tumor protein p53 (TP53) and disease-free survival (DFS) in the entire case series and between DUT or NM23-H1 and DFS in Stage III patients: higher gene expression was associated with shorter DFS. This study provides data on relationships between expression of 5-FU pathway genes and clinical outcome of colorectal cancer patients undergoing 5-FU adjuvant chemotherapy and underscores the predictive role of specific genes. Validation in an independent case series is warranted.

The use of COLD-PCR and high-resolution melting analysis improves the limit of detection of KRAS and BRAF mutations in colorectal cancer.

Fast and reliable tests to detect mutations in human cancers are required to better define clinical samples and orient targeted therapies. KRAS mutations occur in 30-50% of colorectal cancers (CRCs) and represent a marker of clinical resistance to cetuximab therapy. In addition, the BRAF V600E is mutated in about 10% of CRCs, and the development of a specific inhibitor of mutant BRAF kinase has prompted a growing interest in BRAF (V600E) detection. Traditional methods, such as PCR and direct sequencing, do not detect low-level mutations in cancer, resulting in false negative diagnoses. In this study, we designed a protocol to detect mutations of KRAS and BRAF(V600E) in 117 sporadic CRCs based on coamplification at lower denaturation temperature PCR (COLD-PCR) and high-resolution melting (HRM). Using traditional PCR and direct sequencing, we found KRAS mutations in 47 (40%) patients and BRAF(V600E) in 10 (8.5%). The use of COLD-PCR in apparently wild-type samples allowed us to identify 15 newly mutated CRCs (10 for KRAS and 5 for BRAF (V600E)), raising the percentage of mutated CRCs to 48.7% for KRAS and to 12.8% for BRAF (V600E). Therefore, COLD-PCR combined with HRM permits the correct identification of less represented mutations in CRC and better selection of patients eligible for targeted therapies, without requiring expensive and time-consuming procedures.

The intestinal nuclear receptor signature with epithelial localization patterns and expression modulation in tumors.

BACKGROUND & AIMS: The WNT-adenomatous polyposis coli system controls cell fate in the intestinal epithelium, where compartment-specific genes tightly regulate proliferation, migration, and differentiation. Nuclear receptors are transcription factors functioning as sensors of hormones and nutrients that are known to contribute to colon cancer progression. Here we mapped the messenger RNA (mRNA) abundance and the epithelial localization of the entire nuclear receptor family in mouse and human intestine. METHODS: We used complementary high-resolution in situ hybridization and systematic real-time quantitative polymerase chain reaction in samples of normal distal ileum and proximal colon mucosa and tumors obtained from mouse and human adenomatous polyposis coli-initiated tumor models (ie, Apc(Min/+) mice and familial adenomatous polyposis patients) and in cellular models of human colon cancer. RESULTS: We first defined for each receptor an expression pattern based on its transcript localization in the distal ileum and the proximal colon. Then, we compared the mRNA levels between normal intestinal epithelium and neoplastic intestinal tissue. After analyzing the correspondence between mouse and human tumor samples plus genetically modified human colon cancer cells, we used complementary graphic and statistical approaches to present a comprehensive overview with several classification trees for the nuclear hormone receptor intestinal transcriptome. CONCLUSIONS: We defined the intestinal nuclear hormone receptor map, which indicates that the localization pattern of a receptor in normal intestine predicts the modulation of its expression in tumors. Our results are useful to select those nuclear receptors that could be used eventually as early diagnostic markers or targeted for clinical intervention in intestinal polyposis and cancer.

A proteomics approach to identify changes in protein profiles in serum of Familial Adenomatous Polyposis patients.

Familial adenomatous polyposis (FAP) is one of the most important clinical hereditary forms of inherited susceptibility to colorectal cancer and is characterized by a high degree of phenotypic heterogeneity. We used a mass spectrometry driven-proteomic strategy to identify serum molecules differently expressed in FAP patients. The data obtained were subsequently processed by bioinformatic analysis and confirmed by Western blotting. Significant differences were highlighted in the expression of serum proteins of FAP patients. In particular, two proteins (alpha-2-HS-glycoprotein and apoliprotein D) were down-regulated (about 0.5- and 0.7-fold, respectively) in carpeting versus diffuse FAP patients and healthy donors, while alpha-2-antiplasmin was up-regulated (about 1.4-fold). Moreover, mass spectrometry approach enabled us to identify serum biomarkers specific for two distinct clinical form of FAP, i.e. carpeting and diffuse FAP. In particular, vitronectin was up-regulated (more than 1.4-fold) in diffuse FAP patients versus carpeting FAP and versus healthy donors, and two additional proteins (Haptoglobin and alpha-1-acid glycoprotein 1) were up-regulated in 2 out of 3 carpeting FAP patients. Our study suggests that mass spectrometry combined to a strong bioinformatics analysis is a valuable tool for the identification of quali/quantitative differences in the serum proteome of otherwise indistinguishable FAP phenotypes. Moreover, the definition of a proteomic profile, supported by the supervised classification, is a powerful and highly sensitive approach for the identification molecular signatures that are able to outperform the traditional disease markers and can therefore be efficiently applied for the diagnosis and clinical management of FAP patients.

High-resolution melting analysis for rapid detection of KRAS, BRAF, and PIK3CA gene mutations in colorectal cancer.

High-resolution melting analysis (HRMA) provides a valid approach to efficiently detect DNA genetic and somatic mutations. In this study, HRMA was used for the screening of 116 colorectal cancers (CRCs) to detect hot-spot mutations in the KRAS and BRAF oncogenes. Mutational hot spots on the PIK3CA gene, exons 9 and 20, were also screened. Direct sequencing was used to confirm and characterize HRMA results. HRMA revealed abnormal melting profiles in 65 CRCs (56.0%), 16 of them harboring mutations in 2 different genes simultaneously. The frequency of mutations was 17.2% for PIK3CA (11.2% in exon 9 and 6.0% in exon 20), 43.1% for KRAS exon 2, and 9.5% in exon 15 of the BRAF gene. We found a significant association between PIK3CA and KRAS mutations (P = .008), whereas KRAS and BRAF mutations were mutually exclusive (P = .001). This report describes a novel approach for the detection of PIK3CA somatic mutations by HRMA.

Balance between endoscopic and genetic information in the choice of ileorectal anastomosis for familial adenomatous polyposis.

BACKGROUND AND OBJECTIVES: The number of rectal polyps and the site of mutations in the APC (Adenomatous polyposis coli) gene have been used to guide the surgical management in patients with familial adenomatous polyposis (FAP). The aim of this study is to assess the utility of the APC mutation screening compared to the degree of the rectal polyposis in surgical decision making. METHODS: The post-surgical courses of 25 patients submitted to subtotal colectomy with ileorectal anastomosis (IRA) were reviewed. Preservation of the rectum was prospectively decided on the basis of well-defined endoscopic criteria. The number of rectal polyps was assessed preoperatively and every 6-12 months. APC gene was screened for mutations by heteroduplex analysis, single strand conformation polymorphism, in vitro synthesized protein (IVSP), and DNA sequencing. Patients negative for APC mutations were tested for MYH mutations. RESULTS: On the basis of preoperative polyp rectal count we categorized patients as follows: Group I, 5 or fewer adenomas; Group II, 6-9 adenomas; Group III, 10 or more adenomas. After a follow-up ranging from 12 to 225 months we have observed a significant difference of recurrent rectal adenomas between Groups I-II versus III. No difference was detected among patients of Group I and II. The mean number of adenomas/year/patient was 0.67, 1.62, and 9.29 for Group I, II, and III, respectively. Carpeting polyposis of the rectal stump developed in three patients with APC mutation at codon 1309 and two of them needed later proctectomy. Diffuse rectal polyposis was observed in one patient with mutation at exon 9 who had 10 small polyps at time of surgery. Mutation at the 5'-end of APC (codons 144-232), mutation of MYH and unknown APC or MYH mutation were correlated with a low number of polyps both at presentation and follow-up. No IRA patients developed rectal cancer. CONCLUSIONS: In our experience fewer than 10 rectal polyps at presentation can predict a favorable outcome after IRA. Identification of specific germ-line APC or MYH mutation can address the choice of surgical treatment.

Analysis of gene expression profiles reveals novel correlations with the clinical course of colorectal cancer.

In order to discover potential markers of prognosis in colorectal cancer (CRC) we have determined gene expression profiles, using cDNA microarrays in CRC samples obtained from 19 patients in Dukes stages C and D, with favorable clinical course (Dukes C patients, survival >5 years after surgery, group A, n=7) or unfavorable clinical course (Dukes stage C and D patients, survival <5 years after surgery, group B, n=12). Gene expression was measured in RNA from each tumor, using a pool of equal amounts of RNA from all tumors as a reference. To identify and rank differentially expressed genes we used three different analytical methods: (i) Significance Analysis of Microarrays (SAM), (ii) Cox's Proportional Hazard Model, and (iii) Trend Filter (a mathematical method for the assessment of numerical trends). The level of expression of a gene in an individual tumor was regarded as of interest when that gene was identified as differentially expressed by at least two of these three methods. By these stringent criteria we identified eight genes (ITGB2, MRPS11, NPR1, TXNL2, PHF10, PRSS8, KCNK3, JAK3) that were correlated with prolonged survival after surgery. Pathway analysis showed that patients with favorable prognosis had several activated metabolic pathways (carbon metabolism, transcription, amino acid and nitrogen metabolism, signaling and fibroblast growth factor receptor pathways). To further validate individual gene expression findings, the RNA level of each gene identified as a marker with microarrays was measured by real-time RT-PCR in CRC samples from an independent group of 55 patients. In this set of patients the Cox Proportional Hazard Model analysis demonstrated a significant association between increased patient survival and low expression of ITGB2 (p = 0.011) and NPR1 (p = 0.023) genes.

Distribution of Tankyrase-1 mRNA expression in colon cancer and its prospective correlation with progression stage.

We tested Tankyrase-1 mRNA expression in colon cancer patients to evaluate the prognostic role of this parameter by real-time RT-PCR in a retrospective group of 82 unselected patients with colon cancer. Paired cancer and corresponding not affected tissues were used. Laser-assisted microdissection was used to measure Tankyrase-1 mRNA in homogeneous cancer cell populations and in normal colon epithelium of the same patients. Tankyrase-1 mRNA in colon cancers, as a mean, was significantly higher than in paired not affected tissues (p<0.0001), but its level correlates inversely with a cancer progression stage. Survival analysis indicated that lower Tankyrase-1 mRNA expression in colon cancers was significantly associated to reduced patient survival (p=0.019) and disease-free interval (p=0.035), confirmed also in a multi-variate analysis.

Relationships between promoter polymorphisms in the thymidylate synthase gene and mRNA levels in colorectal cancers.

Thymidylate synthase (TS) intratumoural expression may be a prognostic marker and predict outcome of 5-fluorouracil (5-FU)-based chemotherapy in colorectal cancer patients. The TS gene promoter enhancer region contains two different polymorphisms which can influence TS mRNA transcriptional and translational efficiency: a polymorphic tandem repeat sequence (2 or 3 repeats; 2R and 3R) and a single nucleotide polymorphism (SNP), G > C, within the second repeat of the 3R alleles. We studied the relationship between tumoural TS mRNA expression levels and TS gene polymorphisms in the colonic mucosa of 48 colorectal cancer patients. The 3R/3R genotype was characterised by higher TS mRNA levels in the tumour than the 2R/2R-2R/3R genotypes (P = 0.071). Regarding the relationship with the SNP polymorphism, a statistically significant difference in TS gene expression between the 3RG/3RG genotype and 2R/2R-2R/3RC-2R/3RG genotype subset was observed (P = 0.017). No statistically significant correlation was observed between experimental data and baseline clinical-pathological characteristics as well as clinical outcome in the relatively small patient series investigated. This is the first study reporting an association between the TS intra-repeat SNP and gene expression levels in colorectal cancer patients. These results suggest that in 3R/3R patients, the G > C polymorphism may be an important factor in determining TS mRNA expression levels, and warrant further investigation of the role of TS promoter polymorphisms as predictors of sensitivity to 5-FU-based chemotherapy in larger case series.

Mutations of APC and MYH in unrelated Italian patients with adenomatous polyposis coli.

The analysis of APC and MYH mutations in adenomatous polyposis coli patients should provide clues about the genetic heterogeneity of the syndrome in human populations. The entire coding region and intron-exon borders of the APC and MYH genes were analyzed in 60 unrelated Italian adenomatous polyposis coli patients. APC analysis revealed 26 point mutations leading to premature termination, one missense variant and one deletion spanning the entire coding region in 32 unrelated patients. Novel truncating point mutations included c.1176_1177insT (p.His393_PhefsX396), c.1354_1355del (p.Val452_SerfsX458), c.2684C>A (p.Ser895X), c.2711_2712del (p.Arg904_LysfsX910), c.2758_2759del (p.Asp920_CysfsX922), c.4192_4193del (p.Ser1398_SerfsX1407), c.4717G>T (p.Glu1573X) and a novel cryptic APC exon 6 splice site. MYH analysis revealed nine different germline variants in nine patients, of whom five were homozygotes or compound heterozygotes. The mutations included 4 novel MYH missense variants (c.692G>A, p.Arg231His; c.778C>T, p.Arg260Trp; c.1121T>C, p.Leu374Pro; and c.1234C>T, p.Arg412Cys) affecting conserved amino acid residues in the ENDO3c or NUDIX domains of the protein and one novel synonymous change (c.672C>T, p.Asn224Asn). Genotype-phenotype correlations were found in carriers of APC mutations but not in carriers of biallelic MYH mutations, except for a negative correlation with low number of polyps. A distinctive characteristic of patients negative for APC and MYH mutations was a significantly (p<0.0001) older age at diagnosis compared to patients with APC mutations. Moreover, the proportion of cases with an attenuated polyposis phenotype was higher (p = 0.0008) among patients negative for APC and MYH mutations than among carriers of APC or biallelic MYH mutations.

Prognostic value of somatostatin receptor subtype 2 expression in colorectal cancer.

The clinical relevance of the somatostatin receptor subtype 2 (sst2) is well defined in neuroendocrine tumors but it is still a matter of debate whether its expression may have a role also in other tumors not arising from the neuroectoderm. We investigated the prognostic value of the expression levels of sst2 mRNA in a consistent group of patients affected by colorectal cancer. Survival analysis of cancer-related death showed that patients with a high sst2 mRNA expression had an unfavourable outcome (p=0.037) and a significantly shorter disease-free survival (p=0.008). Surprisingly, our findings suggest that sst2 gene overexpression is a feature of colorectal tumors that have a negative outlook; in addition, it may allow additional insight into conventional therapeutic approaches for more aggressive tumors, whose prognosis needs to be improved.

Treatment of desmoids and mesenteric fibromatosis in familial adenomatous polyposis with raloxifene.

BACKGROUND: Among the great variety of extracolonic manifestations of familial adenomatous polyposis, the most serious are desmoids and fibromatosis of the abdominal cavity. These may be a danger to the patient and a concern to the clinician. Pharmacological management of this relentless problem is favored by surgical intervention. At present, however, beneficial actions of medical therapy are not separable from undesirable side effects. METHODS: We studied the effects of 120 mg daily of raloxifene, a non-steroidal benzothiophene, on progressive desmoid tumors and mesenteric fibromatosis by evaluation of lesion size and symptoms in 13 patients with familial adenomatous polyposis, selected on the basis of intra-abdominal localization of the lesion, on refractoriness to other medical treatments, and on estrogen receptor-alpha expression. RESULTS: The patients had a significant response to raloxifene therapy, with complete remission in 8 cases and partial response in 5 cases, evaluated by regression of symptoms and tumor size. Serum biochemical parameters did not show any significant changes. Side effects were never observed. CONCLUSIONS: Although the number of patients included in the study is limited and in spite of some limitations, the available results support that, in the evaluation of response, daily therapy with raloxifene decreases desmoid tumor and mesenteric fibromatosis size and symptoms and does not cause side effects. These findings offer a novel option in the pharmacological treatment of desmoids, leading to medical therapy of these neoplastic lesions in familial adenomatous polyposis patients.