The distribution of intratumoral macrophages correlates with molecular phenotypes and impacts prognosis in colorectal carcinoma.

AIMS: The role of tumour-associated macrophages (TAMs) in colorectal cancer (CRC) remains elusive. In this study, we aimed to examine the correlation between TAMs, clinicopathological features, tumour-infiltrating lymphocytes (TILs) and prognosis in CRC by the use of image analysis. METHODS AND RESULTS: Immunohistochemical staining for CD68 and CD163 was performed as pan-macrophage and M2-macrophage markers, respectively. Each marker was analysed separately for intra-epithelial and stromal area densities. All four macrophage densities showed a significant correlation with one another (P = 0.001). Intra-epithelial CD68+ macrophage densities showed a correlation with pTNM stage (P = 0.008), microsatellite instability (MSI) (P < 0.001), CpG island methylator phenotype (CIMP) (P < 0.001) and TIL densities (P < 0.001). Intra-epithelial CD163+ macrophage densities were associated with perineural invasion, MSI, CIMP and TIL densities (P < 0.001). Stromal CD68+ and CD163+ macrophage densities had a significant relationship with intra-epithelial and stromal CD3+ (P = 0.001 and P < 0.001, respectively) and CD8+ (P < 0.001) T cells. High intra-epithelial CD68+ macrophage density was associated with worse overall survival (HR = 1.386, 95% CI = 1.043-1.843, P = 0.025) and progression-free survival (HR = 1.522, 95% CI = 1.146-2.020, P = 0.004). Intra-epithelial CD68+ macrophage density was also an independent prognostic factor of the progression-free survival (HR = 1.447, 95% CI = 1.076-1.947, P = 0.015) of CRC patients regardless of pTNM stage, lymphatic, venous, and perineural invasions and TIL densities. CONCLUSION: Our results indicate that the density of intratumoural macrophages is a useful prognostic indicator for further stratifying T cell populations in CRC.

Subsets of microsatellite-unstable colorectal cancers exhibit discordance between the CpG island methylator phenotype and MLH1 methylation status.

Although the presence of MLH1 methylation in microsatellite-unstable colorectal cancer generally indicates involvement of the CpG island methylator phenotype (CIMP) in the development of the tumor, these two conditions do not always correlate. A minority of microsatellite-unstable colorectal cancers exhibit discordance between CIMP and MLH1 methylation statuses. However, the clinicopathological features of such microsatellite-unstable colorectal cancers with discrepant MLH1 methylation and CIMP statuses remain poorly studied. Microsatellite-unstable colorectal cancers (n=220) were analyzed for CIMP and MLH1 methylation statuses using the MethyLight assay. Based on the combinatorial CIMP and MLH1 methylation statuses, the microsatellite-unstable colorectal cancers were grouped into four subtypes (CIMP-high (CIMP-H) MLH1 methylation-positive (MLH1m+), CIMP-H MLH1 methylation-negative, CIMP-low/0 (CIMP-L/0) MLH1m+, and CIMP-L/0 MLH1 methylation-negative), which were compared in terms of their associations with clinicopathological and molecular features. The CIMP-L/0 MLH1 methylation-negative and CIMP-H MLH1m+ subtypes were predominant, comprising 63.6 and 24.1% of total microsatellite-unstable colorectal cancers, respectively. The discordant subtypes, CIMP-H MLH1 methylation-negative and CIMP-L/0 MLH1m+, were found in 5 and 7% of microsatellite-unstable colorectal cancers, respectively. The CIMP-H MLH1 methylation-negative subtype exhibited elevated incidence rates in male patients and was associated with larger tumor size, more frequent loss of MSH2 expression, increased frequency of KRAS mutation, and advanced cancer stage. The CIMP-L/0 MLH1m+ subtype was associated with onset at an earlier age, a predominance of MLH1 loss, and earlier cancer stage. None of the CIMP-L/0 MLH1m+ subtype patients succumbed to death during the follow-up. Our findings suggest that the discordant subtypes of colorectal cancers exhibit distinct clinicopathological and molecular features, although the proportion of discordant subtypes is low. The microsatellite-unstable colorectal cancers of the same CIMP status tended to exhibit different clinicopathological features depending on MLH1 methylation status.

Clinicopathologic and molecular characteristics of synchronous colorectal cancers: heterogeneity of clinical outcome depending on microsatellite instability status of individual tumors.

BACKGROUND: The contribution of chromosomal instability, microsatellite instability, and epigenetic instability to the development of synchronous colorectal carcinomas is controversial. OBJECTIVE: This study aimed to investigate the relative roles of microsatellite instability and epigenetic instability in the development of synchronous colorectal cancers. DESIGN: This was a retrospective study of medical records with histologic, immunohistochemical, and molecular examination of stored tissue samples. SETTING: The study took place at Seoul National University Hospital, Korea. PATIENTS: A total of 46 patients with synchronous colorectal cancers and 105 patients with solitary colorectal cancers were included. MAIN OUTCOME MEASURES: Clinicopathologic and molecular characteristics including microsatellite instability, mismatch repair gene expression, CpG island methylator phenotype, and mutation of KRAS and BRAF were analyzed. RESULTS: Patients with synchronous tumors were more likely to be men than those with solitary tumors and had a tendency toward colocalization of individual tumors in the left or right colon. MSI-deficient cancers were more frequent in synchronous than in solitary cancers. The frequencies of CpG island methylator phenotype-high and KRAS and BRAF mutations were not different between synchronous and solitary cancers. No differences between synchronous cancers and solitary cancers were observed in overall survival or progression-free survival. Within the synchronous cancer group, patients with individual tumors discordant for microsatellite instability status had the worst clinical outcome, whereas those with individual tumors concordant for microsatellite instability-deficient status had the best clinical outcome. LIMITATIONS: The study was limited by its retrospective nature. Molecular analysis was performed only on cancerous lesions. CONCLUSIONS: Our findings suggest that microsatellite instability plays a more important role than does epigenetic instability in the development of synchronous colorectal cancers, and that information regarding concordant or discordant microsatellite instability status between individual tumors might help to predict clinical outcome of synchronous colorectal cancers.

Comparison of CpG island hypermethylation and repetitive DNA hypomethylation in premalignant stages of gastric cancer, stratified for Helicobacter pylori infection.

CpG island hypermethylation and genomic DNA hypomethylation are found not only in gastric cancers but also in associated premalignant lesions. Helicobacter pylori infection induces aberrant CpG island hypermethylation in gastric mucosae. However, little is known about the relationship between H. pylori infection and aberrant methylation in premalignant lesions. The present study characterized methylation changes in a subset of genes and repetitive DNA elements (ALU, LINE-1, SAT2) and examined their relationship with H. pylori infection in premalignant lesions of gastric cancers. We performed MethyLight analysis of 25 genes and SAT2 and COBRA analysis of ALU and LINE-1 in 212 gastric tissue samples. H. pylori infection was closely associated with enhanced hypermethylation of CpG island loci in chronic gastritis samples, but this association was not found among intestinal metaplasias, gastric adenomas and gastric cancers. The number of methylated genes was greater in intestinal metaplasia and gastric adenoma samples than in chronic gastritis samples, regardless of H. pylori infection. Methylation of repetitive DNA elements in gastric lesions generally decreased with progression of the gastric lesion along the multistep carcinogenesis. No difference was noted in the number of methylated genes in chronic gastritis or intestinal metaplasia between gastric cancer patients and non-cancer subjects. In conclusion, we found that there was no enhanced CpG island hypermethylation in gastric cancer and premalignant lesions in association with H. pylori infection and our findings suggest that CpG island hypermethylation and repetitive DNA hypomethylation are enhanced with progression of the gastric lesion through the multistep carcinogenesis, regardless of the status of H. pylori infection.

Clinicopathological features of CpG island methylator phenotype-positive colorectal cancer and its adverse prognosis in relation to KRAS/BRAF mutation.

CpG island methylator phenotype (CIMP) is a recently described subset of colorectal cancers (CRC) with widespread methylation of multiple promoter CpG islands. But the prognostic implication of CIMP in CRC has not been clarified. Thus, the aim of the present study was to differentiate the unique characteristics of CIMP from those of microsatellite instability (MSI)-high CRC, especially with regard to prognosis. CIMP, MSI, and mutations of KRAS codons 12 and 13 and of BRAF codon 600 were evaluated in 134 sporadic CRC. Patient survival and other clinicopathological variables were correlated with CIMP or genetic changes. High CIMP, high MSI, and mutations in KRAS or BRAF were detected in 31.3%, 14.2%, 33.6%, and 4.5% of overall CRC, respectively. High CIMP was closely associated with MSI and BRAF mutation but not with KRAS mutation. CIMP-high, microsatellite-stable (MSS) CRC were significantly associated with proximal location and nodal metastasis and had close but non-significant associations with liver metastasis. A worse clinical outcome was found for CIMP-high, MSS CRC with KRAS/BRAF mutation but not for those lacking KRAS/BRAF mutation. The findings support the contention that CIMP-high CRC have distinct clinicopathological and epidemiological features and suggest that the alleged poor clinical outcome of CIMP-high CRC patients is closely associated with the presence of KRAS/BRAF mutation.

Hypermethylation of the COX-2 gene is a potential prognostic marker for cervical cancer.

AIM: The aim of the present study was to evaluate the DNA hypermethylation profiles of 14 genes known to be associated with tumor behavior and their clinical significance in cervical cancer. METHOD: The clinical features of 82 patients with stage IB cervical cancer were analyzed in terms of DNA hypermethylation of 14 genes (hMLH1, p16, COX-2, CDH1, APC, DAPK, MGMT, p14, RASSF1A, RUNX3, TIMP3, FHIT, THBS1, and HLTF). RESULTS: Of 14 genes investigated, only hypermethylation of COX-2 showed significant association with poor disease-free survival (P = 0.001). To further investigate an alteration in COX-2 expression by DNA hypermethylation, immunohistochemistry for COX-2 protein was performed in the cervical cancer tissues. We found no significant association between hypermethylation and expression patterns of the COX-2 gene. CONCLUSIONS: The present results suggest that DNA hypermethylation of the COX-2 gene may be a potential prognostic marker in early stage cervical cancer, the underlying mechanism of which is independent of gene silencing.

Geno- and pheno-typic characterization in ten patients with double-primary gastric and colorectal adenocarcinomas.

BACKGROUND AND AIMS: Although a number of double-primary gastric and colorectal cancers have been known to correlate with the mutator pathway, a possible association with known hereditary cancers regarding geno-pathogenesis has rarely been investigated. This study was intended to identify a possible association of hereditary cancers and the implications of the mutator or tumor-suppressor pathway in double-primary gastric and colorectal cancers. MATERIALS AND METHODS: Fresh colorectal tissues and lymphocytes from ten patients with double-primary gastric and colorectal cancers were obtained consecutively. The mutator pathway was evaluated by detecting hMSH2 and hMLH1 mutations, microsatellite instability (MSI) using 12 microsatellite markers, and hMLH1 promoter region methylation. Protein expressions of hMSH2, hMLH1, APC, E-cadherin, and beta-catenin were identified by immune staining. RESULTS: There was no pathogenic mutation in any introns or exons of hMSH2, hMLH1 or CDH1, and in exons 3, 5, 6, and 15 of CTNNB1. Either MSI or methylator phenotype was found in five gastric cancers and in four colorectal cancers. No patients met the Amsterdam criteria of hereditary nonpolyposis colorectal cancer (HNPCC) or its equivalent of hereditary gastric cancer. Two patients with gastric cancers among their first-degree relatives showed no E-cadherin expression. The two of the three patients with rectal cancers among their first-degree relatives showed mutator phenotype either in the gastric or in the colorectal cancer. A subset of double-primary gastric and colorectal cancers may thereby be categorized as variant forms of hereditary gastric or colorectal cancer. Both cytoplasmic and nuclear beta-catenins were expressed in all gastric and colorectal cancers. Among the gastric and colorectal cancers with either MSI or methylator phenotype, four of five gastric cancers showed both APC and E-cadherin expression, whereas one of four colorectal cancers showed them. CONCLUSION: This may suggest that the mutator pathway and the aberrant tumor suppressor pathway of the APC-E-cadherin may be cooperative or separately activated in the geno-pathogenesis of double-primary gastric and colorectal cancers.

Evaluation of myenteric ganglion cells and interstitial cells of Cajal in patients with chronic idiopathic constipation.

BACKGROUND AND AIMS: The aim of this study was to identify myenteric ganglion cells (MGC) and interstitial cells of Cajal (ICC) from the total colectomy specimen in patients with chronic idiopathic constipation. PATIENTS AND METHODS: Fourteen patients who had severe, intractable, long-standing (mean: 14 years) constipation underwent subtotal colectomy and ileorectal anastomosis. All resected specimens were investigated with hematoxylin and eosin (H&E) and immunohistochemical staining with anti-neurofilament monoclonal antibody NF(2)F(11) for MGC, and c-kit antibody for ICC. The numbers of MGC and ICC were counted for ascending (AC), descending (DC), and sigmoid colon (SC). We compared these data with those from ten control specimens. RESULTS: The number of MGC was significantly smaller in AC and DC of the constipated group than in the control group. Interestingly, SC contained a similar number of MGC. The two staining methods were equally effective for identifying MGC. The total ICC number in the constipated group was markedly lower in every segment. Most anatomical layers of the colon, including the submucosal border, circular muscle, and longitudinal muscle, revealed a similar tendency. However, in the myenteric plexus area there was no significant difference between the two groups. CONCLUSION: A quantitative decrease in MGC and ICC appears to be implicated in chronic idiopathic constipation.

Genotypic analysis at multiple loci across Kaposi's sarcoma herpesvirus (KSHV) DNA molecules: clustering patterns, novel variants and chimerism.

BACKGROUND: The genomes of human Kaposi's sarcoma-associated herpesvirus (KSHV) display several levels of DNA sequence heterogeneity and subgrouping that show distinctive clustering patterns in related human populations. The four major subtype patterns for the hypervariable ORF-K1 protein correlate closely with the principal diasporas resulting from the migration of modern humans out of East Africa and suggest that KSHV is an ancient human virus that is transmitted primarily in a familial fashion with consequent very low recombination rates. However, chimeric genomes have also been detected, especially with regard to the presence of P versus M alleles of the ORF-K15 gene. OBJECTIVES: To understand further the genetic organization and evolutionary history of KSHV, especially with regard to possible new subtypes, recombinant genomes, constant region loci and clustering in particular ethnic groups or among classic versus epidemic cases in the same geographic area. STUDY DESIGN: Direct PCR DNA sequencing was carried out on the ORF-K1 and ORF-K15 genes at the extreme left and right hand sides, as well as on six other internal loci of diagnostic samples collected from 70 new KSHV-positive patients in Israel, South Korea, Sicily, Scandinavia, Brazil, Uganda, South Africa and the US. RESULTS AND CONCLUSIONS: Our overall results from more than 135 KSHV genomes from many different human population groups now provides evidence for seven distinct subtypes of KSHV genomes (referred to as A/P, B/P, C/P, D/P, M, N and Q). However, the two most closely related subtypes (A/P and C/P) are only differentiated at the LHS side of the genome, and the three most distantly related forms (M, N and Q) appear to exist only as small chimeric segments that are remnants from the RHS of more ancient forms of the virus. By analyzing multiple conserved loci across the B subtype genomes that predominate in sub-Saharan Africa, we can also now recognize three to four distinct B genome subgroups with varying patterns of inter and intratypic mosaicism. Analysis of classic KS genomes from Israel has revealed that the ORF-K1 clade referred to as A1' predominates in Ashkenazi Jewish immigrants from Russia, whereas C2 and C6 variants predominate in North African Sephardi Jews. A variety of chimeric genomes containing C2 or C3 ORF-K1 genes are disseminated among classic KS cases throughout Europe and Asia including Israel, Sicily, Scandinavia, South Korea, and Taiwan. Comparison of the genomes from classic versus AIDS-associated KSHV in the US indicates that it was derived originally by reactivation and spread of a subset of the endogenous viruses carried by descendants of immigrants from endemic areas of Northern and Eastern Europe, the Mediterranean and sub-Saharan Africa.