Mitsunori Ushigome

Characterization of Dysplastic Aberrant Crypt Foci in the Rat Colon Induced by 2-Amino-1-Methyl-6-Phenylimidazo[4,5-b]Pyridine

The multistage model of colon carcinogenesis is well established in both humans and experimental animals, and aberrant crypt foci (ACF) are generally assumed to be putative preneoplastic lesions of the colon. However, morphological analyses of ACF have suggested that they are highly heterogeneous in nature and their role in tumorigenesis is still controversial. To better understand the biological significance of ACF in carcinogenesis, morphological and genetic analyses were performed using a rat colon cancer model induced by a food-borne colon carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). ACF of different sizes were collected at weeks 6, 18, 25, and 32 after three cycles of 2-week PhIP feeding (400 ppm in diet) with 4-week intervals on a high-fat diet, and a total of 110 ACF, representing approximately three-quarters of the total ACF, were subjected to histological evaluation. Thirty (27%) were diagnosed as dysplastic ACF, based on cytological and structural abnormalities of crypts. Dysplastic ACF were detected even at week 6 (0.4 per rat), and the numbers increased slightly at later time points, being 0.8, 1.4, and 0.8 per rat at weeks 18, 25, and 32, respectively. The sizes of these dysplastic ACF varied widely from 1 to 16 crypts and 50% (15 of 30) were composed of less than 4 crypts. Immunohistochemical analysis revealed that 83% (25 of 30) of dysplastic ACF demonstrated beta-catenin accumulation; 22 only in the cytoplasm and 3 in both the cytoplasm and nucleus, the latter manifesting a higher grade of dysplasia as compared with the former. Seven dysplastic ACF harbored beta-catenin mutations at codon 32, 34, or 36 in exon 2, and one had an Apc mutation at the boundary of intron 10 and exon 11. Mutations at these sites were also commonly found in colon tumors induced by PhIP. The results of our present study indicate that dysplastic ACF, which accounted for approximately one-fourth of the total ACF, are preneoplastic lesions of colon cancers induced by PhIP in rats.

A role of 18F-fluorodeoxyglucose positron emission/computed tomography in a strategy for abdominal wall metastasis of colorectal mucinous adenocarcinoma developed after laparoscopic surgery

Metastasis to the abdominal wall including port sites after laparoscopic surgery for colorectal cancer is rare. Resection of metastatic lesions may lead to greater survival benefit if the abdominal wall metastasis is the only manifestation of recurrent disease. A 57-year-old man, who underwent laparoscopic surgery for advanced mucinous adenocarcinoma of the cecum 6 years prior, developed a nodule in the surgical wound at the lower right abdomen. Although tumor markers were within normal limits, the metastasis to the abdominal wall and abdominal cavity from the previous cecal cancer was suspected. An abdominal computed tomography scan did not provide detective evidence of metastasis. 18F-fluorodeoxyglucose positron emission/computed tomography (18F-FDG PET/CT) was therefore performed, which demonstrated increased 18F-fluorodeoxyglucose uptake (maximum standardized uptake value: 3.1) in the small abdominal wall nodule alone. Histopathological examination of the resected nodule confirmed the diagnosis of metastatic mucinous adenocarcinoma. Prognosis of intestinal mucinous adenocarcinoma is reported to be poorer than that of non-mucinous adenocarcinoma. In conclusion, this case suggests an important role of 18F-FDG PET/CT in early diagnosis and decision-making regarding therapy for recurrent disease in cases where a firm diagnosis of recurrent colorectal cancer is difficult to make.

Clinical feasibility of sphincter-preserving resection with transanal rectal dissection for low-lying rectal cancer in Japanese patients: a single-center cohort study

Aim: Recently, the transanal down-to-up rectal dissection, a new approach to improve the difficult total mesorectal excision (TME) for low-lying rectal cancer, has been popularized. This study assessed the long-term oncologic and functional outcomes after sphincter-preserving resection combined with transanal rectal dissection (TARD) under direct vision for both complete TME and preservation of the internal anal sphincter (IAS) as much as possible to clarify the clinical feasibility of this approach. Methods: A prospective cohort study was conducted in 90 Japanese patients between April 2003 and March 2012. Results: Abdominoperineal resection (APR) was needed in 17 patients (18.9%) including 14 salvage APRs. Local recurrences occurred in 5 sphincter-preserving resection patients (6.8%). No significant between-group differences were observed in overall survival or 5-year disease-free survival. A significant benefit of preserving the internal anal sphincter completely in sphincter-preserving resection was found on the Wexner incontinence score (P = 0.005), low anterior resection syndrome score (P = 0.002), and visual analogue scale (P = 0.047). Conclusion: TARD, performed under direct vision for both complete TME and preservation of the IAS as much as possible in sphincter-preserving resections for low-lying rectal cancers in Japanese patients, does not negatively impact oncologic outcomes and could have the benefit of minimizing postoperative anorectal dysfunction by preserving the internal anal sphincter.

Multi-panel assay of serum autoantibodies in colorectal cancer

BackgroundAlthough serum p53 autoantibodies (s-p53-Abs) are induced even in the early stages of colorectal cancer, their positive rate is only approximately 20%. Therefore, we assessed the possibility of using other serum autoantibodies to increase the positive rates for detecting colorectal cancer.MethodsAutoantibodies against 17 tumor antigens (p53, RalA, HSP70, Galectin1, KM-HN-1, NY-ESO-1, p90, Sui1, HSP40, CyclinB1, HCC-22-5, c-myc, PrxVI, VEGF, HCA25a, p62, and Annexin II) were evaluated in 279 patients with colorectal cancer and 74 healthy controls. Cutoff values were fixed at mean + 3 standard deviations of serum titers in healthy controls.ResultsAutoantibodies with the highest positive rates were p53 (20%), RalA (14%), HSP70 (12%), and Galectin1 (11%). Combination assays using multiple autoantibodies increased the positive rates based on the number of autoantibodies used. Positive rates of 56, 62, 66, 71, and 73% were obtained with 6, 9, 11, 14, and 17 antibodies, respectively, for the overall disease. Moreover, these autoantibodies showed relatively high positive rates even during stage 0/I disease (55 and 70% with 6 and 17 antibodies, respectively).ConclusionThe measurement of set of 17 autoantibodies allowed autoantibody profiling in patients with colorectal cancer. The combination assay of six tumor antigens (p53, RalA, HSP70, Galectin1, KM-HN-1, and NY-ESO-1) achieved a positive rate of 56%. Such high positive rates will be helpful for detecting colorectal cancer regardless of tumor stages.