Tumor immune microenvironment of primary colorectal adenocarcinomas metastasizing to the liver or lungs.

BACKGROUND: Because of the heterogeneity of metastatic colorectal cancer (mCRC), a genome-wide analysis was performed to characterize the tumor immune microenvironment (TIME). METHODS: RNA-seq analysis of 62 primary CRCs without and 63 with systemic metastasis (SM- and SM+ groups) was conducted, and the data were used in a training set after adjustment by propensity score matching. Samples were further subdivided into those with hepatic metastasis (CHM subgroup), pulmonary metastasis (CPM subgroup), or concurrent CHM and CPM (concurrent group). Validation was done by quantitative reverse-transcription polymerase chain reaction using another 40 primary CRC samples. RESULTS: Compared with the CHM or CPM subgroups, the concurrent group showed upregulated in inflammatory or immune processes, cytokine secretion, and myeloid leukocyte migration. Nine candidate genes were selected: SM-specific IDO1, JAM3, and PDE2A; CHM- or CPM-specific BIRC7; CPM-specific HISI1H2BK, and both SM-specific and CHM- or CPM-specific EPHB6, LPL, THBD, and PPBP. In a validation set of primary CRCs, JAM3 and IDO1 (p = 0.044 and p = 0.036, respectively) were confirmed to show significant upregulation and downregulation, respectively, in the SM+ group, whereas HIST1H2BK (p = 0.017) was significantly upregulated in the CPM subgroup. CONCLUSIONS: Our findings indicate that a host-suppressive TIME is established in the primary tumor of mCRC and identify immune-related site-specific markers of mCRC.

Mechanotechnical faults and particular issues of anastomotic complications following robot-assisted anterior resection in 968 rectal cancer patients.

BACKGROUND: As most risk factors for anastomotic complications (AC) in rectal cancer patients appear to be noncorrectable, it is needed to find the correctable causes. Additionally, the outcomes of indocyanine-green fluorescence imaging (IFI) and robot-stapled anastomosis have yet been undetermined. METHODS: This study retrospectively analyzed 968 consecutive patients with rectal cancer, who underwent curative robot-assisted anterior resections between 2010 and 2018. IFI parameters and stapling features in the surgical records were reviewed, and reconfirmed. RESULTS: AC occurred in 54 patients (5.6%), 34 (3.5%) with anastomotic leakage (AL) and 24 (2.5%) with anastomotic stenosis (AS). Mechanotechnical faults including defective stapling configurations, including angles lesser than or equal to 150° and outer deviation (more than half from the center of the circle) of linear staples, between the two linear staples were independently associated with AL (P < .001 each). IFI significantly reduced AL rate (2.5% vs 5.3%, P = .029) and AS rate (2% vs 18.8%, P = .006), respectively. Robot linear stapling enabled to maintain the obtuse angle during consecutive staplings and reduced console time. AL and AS were independent risk factors for disease-free survival (P = .02) and local recurrence (P = .03), respectively. CONCLUSIONS: AC were associated with some correctable causes, namely, mechanotechnical errors and lack of use of IFI.

Outcomes of ultra-low anterior resection combined with or without intersphincteric resection in lower rectal cancer patients.

PURPOSE: We evaluated the current practice of ultra-low anterior resection (uLAR) in patients with lower rectal cancer and compared uLARs using mostly transabdominal approach with or without intersphincteric resection (ISR). METHODS: A total of 624 consecutive lower rectal cancer patients undergoing curative uLAR were prospectively enrolled as ISR+ vs. ISR- groups (329 vs. 295 patients) between 2005 and 2012. The ISR+ group additionally received levator-sphincter reinforcement after distal resection. RESULTS: The circumferential resection margin (CRM) + rate (≤1 mm) was 2.1 % in the two groups. Postoperative ileus occurred more in the ISR- group than in the ISR+ group (p = 0.02). Substantial erectile dysfunction occurred 1.8 times more frequently in the ISR- group than in the ISR+ group (32 vs. 18.1 %; p = 0.01) among male patients at 2 years postoperatively. The urge to defecate volume and maximal tolerance volume, closely correlated with maximal squeezing pressure and/or mean resting pressure, did not differ between patients with and without chemoradiotherapy until 24 months postoperatively. Nevertheless, the urge to defecate volume was lesser in the ISR- group than in the ISR+ group at 24 months postoperatively (p = 0.022). For 301 patients in which >5 years had elapsed postoperatively, the mean 5-year local recurrence rate was 4.3 %, and the 5-year disease-free and overall survival rates were 78.9 and 92 %, respectively, without differences between the two groups. CONCLUSIONS: Compared with uLAR without ISR, the transabdominal ISR with levator-sphincter reinforcement provides a safe resection plane with competent CRM, concurrently reduces substantial complications, and marginally promotes recovery of neorectal function.

A comparison of the technical and oncologic validity between robot-assisted and conventional open abdominoperineal resection.

PURPOSE: This study was to ascertain whether a robot-assisted (RA) approach to APR might facilitate a cylindrical APR by enabling a deeper pelvic dissection during an abdominal approach, concurrently comparing the feasibility and short-term oncologic outcomes. METHODS: Forty-eight consecutive patients with lower rectal cancer who had undergone curative APR (21 RA vs. 27 open) were prospectively enrolled. The short-term operative outcomes and oncologic feasibility were evaluated and compared. A levator muscle excision was performed concomitantly with the abdominal procedure in the RA group and with the perineal procedure in the open group. RESULTS: No patients in the RA group experienced intraoperative perforation or required conversion to open APR. Overall, a cylindrical APR was performed in 72 % of patients, and subtotal excision of the levator muscle, i.e., either one or both sides of the puborectalis and pubococcygeus muscles, was more likely in the RA group (P = 0.019). A positive CRM was exclusively identified in four open APR patients. The mean number of retrieved lymph nodes was greater in the RA group (20 vs. 16, P = 0.035). There was no difference in perineal morbidity between the two groups (P = 0.445). CONCLUSIONS: The RA approach facilitates an efficient excision in the pelvic region than open APR during the abdominal procedure. The RA approach also demonstrated a trend toward improved oncologic outcomes with equivalent postoperative morbidities than with the open approach.

Completely abdominal intersphincteric resection for lower rectal cancer: feasibility and comparison of robot-assisted and open surgery.

BACKGROUND: Most previous studies of intersphincteric resection (ISR) adopted a two-stage procedure involving abdominal and transanal approaches. We performed completely abdominal ISR via open and a robot-assisted (RA) approaches as treatments for lower rectal cancer (LRC). The RA approach might enable deep dissection and facilitate ISR in patients with restrictive pelvic anatomy. METHODS: A consecutive cohort of 222 LRC patients who underwent completely abdominal ISR (RA ISR, n = 108; open ISR, n = 114) was enrolled prospectively, and their short-term outcomes were evaluated. RESULTS: In a multivariate analysis, ISR was performed more frequently in the RA than in the open group (82.6 vs. 67.9 %, p = 0.008). The number of harvested lymph nodes was >12 in both groups. A positive distal resection margin was not observed in either group, and a positive circumferential resection margin was found in one patient in the RA group. Overall morbidity did not differ between the groups. Moderate to severe sexual dysfunction occurred 2.7-fold more frequently in the open group (p = 0.023) among male patients ≤65 years. Mean Wexner's fecal incontinence scores at postoperative months 6 and 12 were greater in the open group than in the RA group (p < 0.05). CONCLUSIONS: Completely abdominal ISR may be feasible in the treatment of LRC, based on a short-term study. Furthermore, RA ISR had equivalent oncological outcomes and slightly improved functional recovery relative to open ISR.

Abdominoperineal resection and low anterior resection: comparison of long-term oncologic outcome in matched patients with lower rectal cancer.

PURPOSE: The current study aimed to compare the oncologic outcome and pattern of metastasis after abdominoperineal resection (APR) and low anterior resection (LAR) treating lower rectal cancer. METHODS: A total of 804 patients undergoing curative resection (R0) were enrolled prospectively. The APR and LAR groups (n = 402, respectively) were matched for gender, age, and stage, for a retrospectively comparative analysis. RESULTS: In a multivariate analysis with potential variables, APR itself was not a risk factor for increased local recurrence (LR) or reduced survival (P = 0.243-0.994). Circumferential resection margin (CRM) involvement as an operation-related risk was 1.6-fold more frequent in the APR group and was significantly associated with LR and systemic recurrence (OR, 2.487-4.017; P < 0.01). Circumferential margin positivity (CRM+) was concurrently correlated with advanced stage, larger tumor (long diameter, >4 cm), and longer sagittal midpelvic diameter (>10 cm) in a multivariate analysis (P < 0.001-0.05). The site of metastasis did not differ between the two groups, with the exception of lung metastasis which was more frequent in the APR group (APR vs. LAR: 15.9 vs. 10 %, P = 0.015). In the APR group, CRM+ and the presence of an infiltrating tumor were correlated with disease-free survival (hazard ratio (HR), 1.644 and 1.654, respectively), whereas elevated serum carcinoembryonic antigen and LVI+ were correlated with overall survival (HR, 1.57 and 1.671, respectively), in a multivariate analysis with potential variables (P < 0.05). CONCLUSIONS: When performed with appropriate skill to achieve R0 resection, APR can be used safely without impairing oncological outcome, although sphincter-preserving surgery should remain the preferred option.

Genome-wide identification of chemosensitive single nucleotide polymorphism markers in colorectal cancers.

Improved methods for predicting chemoresponsiveness involving the identification of polymorphic markers is highly desirable, considering narrow therapeutic index and frequent resistance to anti-cancer regimens. The genome-wide screening of chemosensitive single nucleotide polymorphisms (SNPs) was undertaken in association with in vitro chemosensitivity assays in 104 colorectal cancer patients for the initial screening step. Allele frequency, linkage disequilibrium, potential function, and Hardy-Weinberg equilibrium of the candidate SNPs were then determined for the identifying step. Finally, clinical association analysis in the other 260 evaluable patients or cell viability assays of transfected RKO cells was used to verify candidate SNPs for the validation step. In total, 12 SNPs to six regimens were initially chosen during the screening and identifying steps. In patients receiving fluoropyrimidine-based adjuvant chemotherapy, the substitution alleles of GPC5 rs553717 (AA) correlated significantly with tumor recurrence and shorter disease-free survival (P = 0.019 and 0.023, respectively). Interestingly, RKO cells expressing mutant GPC5 showed enhanced cell death in response to 5-FU in cytotoxicity assays. Patients that were homozygous for the reference alleles SSTR4 rs2567608 (AA) and EPHA7 rs2278107 (TT) showed lower disease control rates in response to irinotecan and oxaliplatin regimens, respectively, than those with substitution alleles (P = 0.022 and 0.014, respectively). Thus, we identified chemosensitive SNP markers using a novel three step process of genome-wide analysis consisting of in vitro screening, identification, and validation. The candidate chemosensitive SNP markers identified in our study, including those identified in vitro, can now be further verified in a large cohort study.

Promoter methylation of specific genes is associated with the phenotype and progression of colorectal adenocarcinomas.

BACKGROUND: Promoter methylation of colorectal cancer-related genes were examined with respect to phenotype and tumor progression. MATERIALS AND METHODS: We assayed promoter methylation of 11 genes including established CpG island methylator phenotype (CIMP) markers (MLH1, MINT1, MINT2, MINT31, p16 ( INK4a ), p14 ( ARF ), and CACNA1G) and four genes (COX2, DAPK, MGMT, and APC) frequently methylated in colorectal cancer in 285 patients with sporadic colorectal cancer. RESULTS: CIMP+ tumors were more than two times more frequent among high-frequency microsatellite instability tumors (MSI-H) than in tumors without MSI (P < or = .0001-.002). COX2 and DAPK methylation were significantly associated with CIMP+ and MSI. KRAS showed tendency toward more frequent codon 12-13 mutations identified in tumors with APC and p16 ( INK4a ) methylation than in those with unmethylation (P = .033 and .05, respectively). Additionally, tumors with synchronous adenoma were associated with p16 ( INK4a ) methylation (P = .004). The p16 ( INK4a ) methylation was significantly associated with poor overall and disease-free survival in 131 rectal cancer patients who underwent curative operation, according to multivariate analyses (relative risk [RR] = 0.317 and 0.349; P = .033 and .024, respectively). Specifically, in 175 stage II and III patients receiving adjuvant-based fluoropyrimidine chemotherapy, p16 ( INK4a ) methylation and MINT31 unmethylation showed a significant or tendency toward an association with recurrence and DFS (P = .007-.032). CONCLUSIONS: The study suggests that specific CIMP markers, such as p16 ( INK4a ) and MINT31, should be further verified as potential epigenetic targets for the design of efficient chemotherapy regimens. We also identified a subset of colorectal cancer, possibly comprising APC methylation-KRAS mutation-p16 ( INK4a ) methylation.

Evaluation of novel histone deacetylase inhibitors as therapeutic agents for colorectal adenocarcinomas compared to established regimens with the histoculture drug response assay.

BACKGROUND AND AIMS: This study was to evaluate the efficacy of histone deacetylase (HDAC) inhibitors in colorectal cancer together with other established regimens. MATERIALS AND METHODS: Chemosensitivities of 114 colorectal cancer patients to established regimens (fluorouracil (5-FU with leucovorin (FL), capecitabine, FL with irinotecan (FLIRI), and FL with oxaliplatin (FLOX)) as well as five hydroxamic acid derivatives (suberoylanilide hydroxamic acid, PXD101, and three novel candidates of CG-1, CG-2, and CG-3) were comparatively evaluated using the histoculture drug response assay. RESULTS: The chemosensitivity with established regimens was between 34.2% and 52.6%, when the cutoff value of the inhibition ratio was set at 30%, and between 54.5% and 84.1% with HDAC inhibitors. All HDAC inhibitors displayed synergistic effects in combination with established regimens of FLOX and FLIRI (P < or = 0.0001-0.002). Advanced T- and N-category tumors and patients with synchronous adenoma displayed higher chemosensitivity to CG-3, CG-2, and CG-1, respectively, on a multivariate analysis (P = 0.023, 0.044, and 0.045, respectively). Tumors with mismatch repair defects were closely correlated with chemosensitivities to combined regimens of PDX101 with FLOX and FLIRI (P = 0.044 and 0.048, respectively). CONCLUSIONS: Our findings firstly demonstrated the chemo-responsiveness of colorectal cancers to HDAC inhibitors with therapeutic efficacy comparable to the established regimens. Additionally, tumor growth and heredity were significantly associated with specific regimens, supporting their possible role as chemosensitive predictors.

Ovarian metastases from colorectal cancer: a clinicopathological analysis of 103 patients.

OBJECTIVE: To improve management of ovarian metastasis through assessment of clinicopathological features and treatment outcomes associated with ovarian metastasis from colorectal cancer. METHOD: We recruited 103 subjects who were diagnosed with ovarian metastasis and subjected to surgery between June 1989 and December 2005. Clinical and pathological variables were evaluated. Survival and its associated factors were analysed with a median follow-up of 31 months after ovarian surgery (range 1-129 months). RESULTS: The mean age at diagnosis was 46 years (range 14-72 years), synchronous ovarian metastasis occurred in 74 patients and metachronous in 29 patients. The primary tumour was more commonly associated with the colon rather than the rectum (84/1608, 5.2%vs 19/1534, 1.2%, P < 0.001). Combined metastases occurred in 69 patients (67%). Complete resection was achieved in 34 (33%) patients without other metastases. The estimated 5-year disease free survival and overall survival rate were 40.1% and 26.6%, respectively. From univariate analysis, lymphovascular invasion (35.6%vs 12.8%, P = 0.034), combined metastasis (50.9%vs 15.6%, P = 0.0035) and bilaterale ovarian metastasis (36.4%vs 10.6%, P = 0.015) were identified as significant poor prognosis factors, and from multivariate analysis combined metastasis and bilaterale ovarian metastasis were significant (P = 0.034 and P = 0.015, respectively). CONCLUSION: This study suggests a role for regular follow-up computed tomography scans within 6 months postoperatively and tumour marker assays for the early detection of ovarian metastasis in premenopausal women after primary surgery, especially in colonic patients with poor prognostic factors.

Individual tumorigenesis pathways of sporadic colorectal adenocarcinomas are associated with the biological behavior of tumors.

Clinicopathologic features of sporadic colorectal adenocarcinomas were compared using integrated data from 224 [corrected] patients subjected to curative resection. Individual steps in the tumorigenesis pathway, that is, adenomatosis polyposis coli (APC), Wnt-activated, base excision repair mutations, mismatch repair defects, RAF-mediated, transforming growth factor (TGF)-beta-suppressed, bone morphogenic protein (BMP)-suppressed, and p53 alterations, were examined in terms of genetic and epigenetic changes, as well as protein expression. Genetic and molecular alterations of right colon cancers were distinct from those of left colon and rectal cancers. Rectal cancers showed the attenuated phenotype of left colon cancers. Tumors most frequently displayed either TGF-beta- or BMP-suppressed alterations (81.2%), followed by RAF-mediated alterations (78.6%), and mismatch repair defects (38.4%), constituting a total of 24 integrated pathways. Tumors lacking APC mutations or carrying the RAF alteration (V600E) were frequently associated with lymphovascular invasion and lymph node metastasis (P < 0.05). Poorly differentiated or mucinous adenocarcinomas were generally associated with high level microsatellite instability, Axin2 suppression, TGF-beta1 or BMPR1A suppression, loss of heterozygosity of D18S46 or D18S474, and absence of base excision repair mutations (P < 0.0001-0.05). Early tumor recurrence was significantly correlated with lack of APC mutations (P = 0.036). Moreover, tumors that concurrently displayed APC/Wnt-activated, TGF-beta/BMP-suppressed, and p53 alterations were significantly predisposed to early recurrence (P = 0.026). Our data clearly indicate that particular steps or pathways of colorectal tumorigenesis are closely associated with characteristic clinicopathologic features that, in turn, determine biological behavior, such as tumor growth, invasion, and recurrence.

MYH, OGG1, MTH1, and APC alterations involved in the colorectal tumorigenesis of Korean patients with multiple adenomas.

This study was done to characterize base excision repair (BER) genes and adenomatous polyposis coli (APC) alterations in the tumorigenesis of multiple colorectal adenomas in Korean patients. In total, 217 adenomas (mean number = 10) and 117 cancers were available from 143 patients. The heterozygous genotype of OGG1 c.1-18G>T was closely associated with multiple adenoma families (P < 0.001), while MYH A359V mutation exhibited a tendency (P = 0.053). MYH R170G mutation was exclusively identified in one patient. The G:C>T:A transversion or attenuated familial adenomatous polyposis (AFAP) mutations of APC was identified in the specific genotypes of BER variants. Tubular adenomas or adenomas with none-to-mild dysplasia were significantly associated with polymorphic genotypes of OGG1 IVS4-15 and S326C. In addition, large and pedunculated adenomas were more frequent in patients with G:C>T:A transversion and AFAP mutations of APC, respectively. However, BER variants were not associated with mismatch repair or altered p53 protein expression. Conclusively, two novel mutations of MYH and a novel OGG1 polymorphism seemed to be associated with multiple colorectal adenomas in Korean families, differing from those in other ethnic groups. Some BER variants involved in specific APC mutations are associated with characteristics of histogenesis other than altered mismatch repair or p53 pathway.

Resection after preoperative chemotherapy versus synchronous liver resection of colorectal cancer liver metastases: A propensity score matching analysis.

This study aimed to determine the prognostic effects of preoperative chemotherapy for colorectal cancer liver metastasis (CLM).We retrospectively evaluated 2 groups of patients between January 2006 and August 2012. A total of 53 patients who had ≥3 hepatic metastases underwent resection after preoperative chemotherapy (preoperative chemotherapy group), whereas 96 patients who had ≥3 hepatic metastases underwent resection with a curative intent before chemotherapy for CLM (primary resection group). A propensity score (PS) model was used to compare the both groups.The 3-year disease-free survival (DFS) rates were 31.7% and 20.4% in the preoperative chemotherapy and primary resection groups, respectively (log-rank = 0.015). Analyzing 32 PS matched pairs, we found that the DFS rate was significantly higher in the preoperative chemotherapy group than in the primary resection group (3-year DFS rates were 34.2% and 16.8%, respectively [log-rank = 0.019]). Preoperative chemotherapy group patients had better DFSs than primary resection group patients in various multivariate analyses, including crude, multivariable, average treatment effect with inverse probability of treatment weighting model and PS matching.Responses to chemotherapy are as important as achieving complete resection in cases of multiple hepatic metastases. Preoperative chemotherapy may therefore be preferentially considered for patients who experience difficulty undergoing complete resection for multiple hepatic metastases.

Efficacy of 3-dimensional endorectal ultrasonography compared with conventional ultrasonography and computed tomography in preoperative rectal cancer staging.

BACKGROUND: This study was performed to verify reports of the decreased accuracy of endorectal ultrasonography (EUS) in preoperative staging of rectal cancer, and to compare the efficacy of 3-dimensional (3D) EUS with that of 2-dimensional (2D) EUS and computed tomography (CT). METHODS: Eighty-six consecutive rectal cancer patients undergoing curative surgery were evaluated by 2D EUS, 3D EUS, and CT scan. RESULTS: The accuracy in T-staging was 78% for 3D EUS, 69% for 2D EUS, and 57% for CT (P < .001-.002), whereas the accuracy in evaluating lymph node metastases was 65%, 56%, and 53%, respectively (P < .001-.006). Examiner errors were the most frequent cause of misinterpretation, occurring in 47% of 2D EUS examinations and in 65% of 3D EUS examinations. By eliminating examiner errors, the accuracy rates in T-staging and lymph node evaluation could be improved to 88% and 76%, respectively, for 2D EUS, and to 91% and 90%, respectively, for 3D EUS. Conical protrusions along the deep tumor border on 3D images were correlated closely with infiltration grade, advanced T-stage, and lymph node metastasis. CONCLUSIONS: We found that 3D EUS showed greater accuracy than 2D EUS or CT in rectal cancer staging and lymph node metastases. Concrete 3D images based on tumor biology appear to provide more accurate information on tumor progression.

Analysis of surgical treatments for circumferentially protruding haemorrhoids: complete excision with repair using flaps versus primary excision with secondary suture-ligation.

BACKGROUND: Circumferentially protruding haemorrhoids (CPH) are troublesome lesions for both patients and surgeons, and in most cases demand surgical intervention. However, such surgery carries the risks of complications and recurrence. This study compared two surgical procedures in order to identify the optimal approach for CPH. METHODS: All patients underwent an open haemorrhoidectomy for primary haemorrhoids, after which patients underwent either of the two procedures for secondary haemorrhoids. Group 1 (n = 104) comprised patients who underwent submucosal excision with repair using remnant anodermal flaps; this procedure was performed between 1991 and 1996. Group 2 (n = 113) comprised patients who underwent suture-ligation; this procedure was performed between 1997 and 2002. Surgical outcomes including surgical variables, wound healing, complications and patient satisfaction were compared between the two groups. RESULTS: For group 2, surgical time and duration of analgesic use (mean +/- SEM, 22 +/- 0 minutes and 3 +/- 0 days, respectively) were significantly shorter than for group 1 (28 +/- 1 minutes and 4 +/- 0 days, respectively; p < 0.001 for both comparisons). In terms of complication rates, there was no significant difference between group 2 (15 patients, 14%) and group 1 (25 patients, 22%), and most complications were satisfactorily treated using conservative management. Skin tags and perianal abscesses were more frequent in group 1 than in group 2. The final follow-up was undertaken at 6 months postoperatively, at which time there were no recurrences in patients of either group. For both groups, over 90% of patients reported that they were satisfied with the outcome of surgery. CONCLUSION: Although both surgical approaches were successful for treating CPH, open haemorrhoidectomy for primary haemorrhoids combined with suture-ligation for secondary haemorrhoids appears to be the optimal approach considering its rapidity, simplicity and lower associated costs.

Utility of indocyanine-green fluorescent imaging during robot-assisted sphincter-saving surgery on rectal cancer patients.

BACKGROUND: There have been few studies describing the use of indocyanine green (ICG) fluorescent imaging during robot-assisted (RA) sphincter-saving operations (SSOs) and assessing its potential role in reducing anastomotic leak (AL). METHODS: A consecutive cohort of 436 rectal cancer patients who underwent curative RA SSOs were prospectively enrolled during 2010-2014, including 123 patients with ICG imaging (ICG+ group) and 313 patients without ICG imaging (ICG- group). RESULTS: ICG imaging appeared to be helpful in identifying competent perfusion of the bowel adjacent to the anastomosis in 13 patients (10.6%) who might be susceptible to bowel ischaemia, including restrictive mesocolon. AL was remarkably greater in the ICG- group compared with the ICG+ group (5.4% vs 0.8%; p = 0.031). CONCLUSIONS: ICG imaging during RA SSO provides accurate real-time knowledge of the perfusion status at or near the anastomosis, specifically reducing AL in patients who may incur bowel ischaemia. Copyright © 2015 John Wiley & Sons, Ltd.

Genetic and pathologic changes associated with lymphovascular invasion of colorectal adenocarcinoma.

Lymphovascular invasion (LVI) is a biological manifestation of aggressive behavior in colorectal cancer. This study sought to identify and examine the association between genetic and pathologic alterations implicated in this invasive tumor progression. We consecutively recruited 81 and 79 colorectal cancer patients with and without LVI, respectively. Biological changes were evaluated by clinicopathological parameters together with CEA and E-cadherin expressions using immune staining. Allelic loss or MSI was examined using 10 microsatellite markers on chromosomes 10, 16, 18, and TGFbetaRII, possibly associated with colorectal cancer. The germline mutation of BMPR1A and SMAD4 was also sought. Tumor stage and lymph node metastasis were significantly greater in patients with LVI tumor than without it (P < 0.001). Decreased CEA expression was closely correlated with allelic loss or MSI at D16S421, D18S46, and D18S474 (P = 0.004-0.047). Allelic loss at D10S14 was specific to LVI tumors (P = 0.007). Using multivariate analysis, allelic loss at D18S46 significantly correlated with histological differentiation (P = 0.02). In addition, allelic loss and MSI at D18S474, histological differentiation, and expression of CEA and E-cadherin were closely associated with the progression of LVI (P = 0.005-0.049). However, no germline mutation in BMPR1A or SMAD4 was detected in all patients regardless of LVI status. In summary, in a subset of colorectal cancers, histological differentiation and expression of CEA or E-cadherin appear to determine aggressive behavior such as LVI. These changes are closely associated with chromosomal alterations at 10q22-23, 16q22 and 18q21, which carry several tumor suppressor genes.

Experimental radioimmunoguided surgery for peritoneal metastases of gastric cancer using anticarcinoembryonic antigen-specific T84.66 F(ab')2.

PURPOSE: In gastric cancer, peritoneal dissemination is the most frequent cause of the noncurative resection and recurrence after curative resection. We therefore evaluated the feasibility of radioimmunoguided surgery (RIGS) in the treatment of peritoneal metastases of gastric cancer and the use of anti-CEA-specific T84.66 F(ab')2 as an efficient immune agent. METHODS: Two human gastric cancer cell lines, MKN45 and RF48, were intraperitoneally xenografted into nude mice, which were later injected with 125I-labeled T84.66 F(ab')2. Peritoneal tumors were localized by RIGS 5 days after antibody injection. The minimum number of cells detected by a gamma probe was assayed by in vitro tumor cell localization. RESULTS: We observed 37 peritoneal metastases: 8 invisible (long diameter, <1 mm), 6 small (1- < 5 mm), and 23 large (> or =5 mm) tumors. The accuracy, sensitivity and specificity of RIGS in detecting peritoneal metastasis were 82% (69/84), 76% (28/37), and 87% (41/47), respectively. RIGS accuracy did not differ with respect to tumor diameter. Mean labeling indices over minimal and maximal normal counts were 6.1+/-1.2 (mean +/- SEM) and 4.7+/-1, respectively. Mean scores of CEA immunostaining and silver grains in tumors were significantly higher than those in the nontumor-bearing peritoneum (P < 0.001). There was a close correlation among radioactivity, immunostaining and microautoradiography (P < 0.001-0.005). We observed six false-positive and nine false-negatives which may have been due to high blood background and negative radioimmune reactivity, respectively. CONCLUSIONS: 125I-labeled T84.66 F(ab')2 efficiently targeted peritoneally disseminated gastric cancer cells, suggesting that RIGS using this immune agent may accurately detect occult peritoneal metastases in patients with gastric cancer.

Characterization of mutator phenotype in familial colorectal cancer patients not fulfilling amsterdam criteria.

PURPOSE: Although the mutator phenotype, including genetic and epigenetic alterations of the mismatch repair (MMR) system, seems to be pronounced in familial colorectal cancer, there have been few integrative studies comprising the entire mutator pathway. This study was done to identify the entire mutator pathway determining risk factors in patients with familial colorectal cancer not fulfilling the Amsterdam criteria. EXPERIMENTAL DESIGN: We consecutively recruited 134 colorectal cancer patients with a family history of accompanying cancers. Patients with hereditary nonpolyposis colorectal cancer meeting the Amsterdam criteria, familial adenomatous polyposis, or those receiving preoperative radiotherapy were excluded. Mutator phenotype was assessed by assaying microsatellite instability (MSI) at 24 markers, hMLH1-promoter methylation, mutations at MMR genes (hMLH1, hMSH2, hMSH6, and hPMS2), and immune staining of MMR proteins (hMLH1, hMSH2, hMSH6, hPMS1, and hPMS2). RESULTS: Of the 208 cancers in first-degree and/or second-degree relatives of patients, colorectal and gastric cancers (81%) were most common. Of the 134 proband colorectal cancers, 23 (17%) were MSI in high level, and 32 (24%) were MSI in low level. MMR alterations, including known polymorphism and splicing substitution, were identified in eight patients (6%). Twenty-eight tumors with mutator phenotype were further identified by hMLH1-promoter methylation and/or loss of MMR protein expression. In 51 tumors (38%), mutator phenotype was associated with right-sided colon cancer (P < 0.001) and younger age at onset (P=0.032), but the number of patients with a mutator phenotype did not differ with respect to inheritance patterns of accompanying cancers, either successive or horizontal transmission (P=0.815). Familial impact value, which differentially associated the degree of relatives with all accompanying cancers, effectively discriminated MSI in high level from microsatellite stable/MSI in low level tumors. CONCLUSION: Familial colorectal cancer may be associated with multiple occurrences of colorectal or accompanying cancers inherited by dominant or recessive transmission. MMR gene mutations, however, are less associated with mutator phenotype in familial colorectal cancer.

Correlation between hMLH1/hMSH2 and p53 protein expression in sporadic colorectal cancer.

BACKGROUND/AIMS: The aim of this study was to analyze expression of hMLH1 and hMSH2 mismatch repair proteins in terms of p53 protein expression and clinicopathological parameters in sporadic colorectal cancer. METHODOLOGY: Four hundred and two cases of curative colorectal surgery for primary colorectal cancer were included in this study (patients with a familial history of colorectal cancer and familial adenomatous polyposis were not included). Clinicopathological parameters were reviewed retrospectively. HMLH1, hMSH2 and p53 protein expression in tumor tissue sections was determined using immunohistochemical staining with specific monoclonal antibodies. RESULTS: Of the 402 cases, immunohistochemical analysis showed 35 (8.7%) had loss of expression of hMLH1, 19 (4.7%) had loss of expression of hMSH2, and three cases (0.7%) had loss of expression of both proteins. Multivariate analysis showed that early age of onset (p=0.023), right side dominance (p<0.001) and poorly differentiated or mucinous cell type (p<0.001) were associated with loss of expression of hMLH1 or hMSH2. Loss of expression of hMLH1 or hMSH2 correlated with low p53 expression (p<0.001). In terms of clinicopathological parameters, p53 expression was associated only with hMLH1 or hMSH2 expression. CONCLUSIONS: Colorectal cancers not expressing hMLH1 or hMSH2 may have distinct features from those expressing these mismatch repair proteins. p53 expression appears to be implicated in a compensatory pathway with mismatch repair proteins.