Takao Itoi

APC, K-ras codon 12 mutations and p53 gene expression in carcinoma and adenoma of the gall-bladder suggest two genetic pathways in gall-bladder carcinogenesis

Currant histopathoiogical evidence suggests that gall‐bladder cancer has two main morphological pathways for Its development: de novo (ab Inltlo) origin and adenoma‐carcinoma sequence. In order to investigate the genetic difference between them, APC mutations were examined by RNase protection analysis, K‐ras mutations by nested porymerase chain reaction‐restriction fragment length polymorphism analysis, and p53 gene overexpression by immunoriisto‐chemical analysis in both tumors and benign lesions of the gall‐bladder. Overexpression of the p53 gene was detected in 105 of 164 (64%) de novo carcinomas regardless of size and depth of Invasion, but not in 16 tumors of carcinoma‐ln‐pyloric‐gland‐type adenoma, or In 51 adenomas (47 pyloric gland‐type and 4 Intestinal‐type). K‐ras codon 12 mutation was detected in 4 of 40 (10%) de novo carcinomas, ail four being associated with p53 gene overexpression, but not in 12 tumors of carcinoma in adenoma or 16 adenomas (14 pyloric gland‐type and 2 intestinal‐type). APC mutation was not found in 16 de novo carcinomas or the one pyloric gland‐type adenoma examined. These results suggest that there are two distinct genetic pathways in gall‐bladder carcinogenesis; that is, de novo carcinoma develops from a predominant p53 alteration with low K‐ras mutation, and carclnoma‐in‐pylortc‐gland‐type adenoma develops from p53‐, K‐ras‐, and APC‐gene‐unrelated, as yet unknown, alteration.

p53 and Ki-67 immunoreactivity and nuclear morphometry of ‘carcinoma-in-adenoma’ and adenoma of the gall-bladder

Twenty lntramucosal tumors of ‘carclnomaln‐adenoma’ and 43 ademas (39 pylorlc gland type, 4 Intestinal type) of the gall‐bladder were studied to establish more precise histo‐logical criteria of carcinoma or adenoma In cases of ‘carcinoma In pyforic gland type adenoma’, to compare carcinoma In adenoma with pure, that Is, without adenomatous components, carcinoma, and to confirm the benign nature of spin‐dle cell fd in the adenomas. Ki‐67 and p53 immunostaining and nuclear morphomety were used. Eight pure intramucessl cancers were used as controls. The formalin‐fixed, paraffln+mbedded sections were stained with p53 and Ki‐67 antibodies. Splndle cell foci were observed only In the adenoma area of the pyloric gland type, wlth a frequency of 23% In 39 adenomas, and of 45% in 20 tumors of carclnoma‐lrradenoma. Ki‐67 staining was negative in 129 of 130 spin‐die cell foci examlned, regardless of their size, and positive in only one focus (550 pm in size, Ki‐67 Index 0.2%). All of the spindle cell foci were negative for p53 stain. The Ki‐67 positive index was 36.6 ± 5.6% In the 8 pure carcinomas, and 12.5 ± 1.9% in the cancer areas of 16 tumors with carcinoma‐in‐adenoma, while it was 7.9 ± 1.7% in the adenoma areas of 16 tumors with carcinoma‐in‐adenoma and 4.9 ± 0.5% in the 32 pure pyloric gland adenomas. The p53‐protein over‐expression was found in seven of eight pure intramucosal cancers, and in one of 16 cancer components of carclnoma‐in‐adenoma. However, it was not found in any of 16 adenoma components of carcinoma‐in‐adenoma, and 35 adenomas. Cells of the cancer tissue of carcinoma‐In‐adenoma showed a significantly larger nuclear area and a larger nuclear minor axis than those of the pyloric gland type adenomas, as well as other architectural and cytologic abnormalities differing from the features of adenomas. These results suggest that clustered spindle cells do not indmte a malignant transformation of adenoma cells and that carcinomas in carcinoma‐in‐adenoma are dtfferent from pylorlc gland type adenomas In terms of morphology and proliferative activity. Moreover, the results of the present study indicate that carcinomas In carcinoma‐ln‐adenoma are lower In malignancy than pure carcinomas, and that their genetic abnormaltty may differ from that of pure carcinomas.

Correlation of p53 protein expression with gene mutation in gall‐bladder carcinomas

The correlation of p53 protein expression and p53 mutation of 33 gall‐bladder carclnomas was studied accordlng to the depth of invasion and grade of cytological atypia. Overexpresslon of p53 protein was detected by immunostaining in seven (70.00/) of 10 intramucosal and in 16 (69.6%) of 23 invasive carcinomas. p53 mutation was detected in five (71.4%) of the seven intramucosal carcinomas with overexpresslon and In eight (50.0%) of the 16 invasive cancers with overexpression and in one (10%) of the 10 non‐overexpressing carclnomas at exons 5–8 by nested polymerase chain reactlon‐single‐strand conformatlon polymorphism. The overexpression of p53 protein was present In nine (56.3%) of 16 low‐grade carcinomas and In 14 (82.3%) of 17 high‐grade carcinomas. In cases of overexpresslon, p53 mutatlon was detectable in four (44.4%) of nlne lowgrade and in nlne (64.3%) of 14 high‐grade carclnomas. In total, p53 mutation was verified In 56.5%0 (13123) of cases involving protein overexpression and in 10% (1/10) of cases of nonoverexpresslon. The sensltivity of p53 mutation was 56.5% (13/23), the specificity was 90.0% (9/10) and the validity was 1.47. in conclusion, our study indicates that p53 protein overexpression correlates well wlth gene mutatlon and that p53 alteration may be related to increaslng grade of cytologic atypla of carclnomas.

Prevention of Post-Endoscopic Retrograde Cholangiopancreatography Pancreatitis

Endoscopic retrograde cholangiopancreatography (ERCP) is an essential modality for the diagnosis and therapy of pancreatobiliary disease. However, complications of ERCP-related procedures are also common. Post-ERCP pancreatitis (PEP), the most common and potentially serious complication of ERCP-related procedures, occurs in 1 9% of all procedures (1-16). Moreover, the PEP rate increases to 10 40% in cases with risk factors (116). In most cases, PEP is generally mild and requires only conservative treatment. However, substantial complications, occasionally fatal, can occur. Therefore, it is imperative to establish a strategy for preventing PEP based on medical, social, and economical circumstances. The prevention of PEP, according to various studies, is presently based on the elucidation of its underlying mechanisms, the identification of its risk factors, the administration of pharmacological drugs, and endoscopic procedures such as pancreatic stenting.

AB127. P103. Evaluation of new stent for EUS-guided pancreatic duct drainage: long-term follow-up outcome

Background: EUS-guided pancreatic duct drainage (EUSPD) has been reported as an alternative for failed conventional endoscopic retrograde cholangiopancreatography (ERCP). However, there are few dedicated devices for EUS-PD. Recently, we have developed a new plastic stent dedicated for EUS-PD and have conducted a feasibility study to evaluate its efficacy. In the present study, we evaluated the long-term efficacy of this new plastic stent. Methods: Thirty-two patients (62±15.2 years old, 16 men) with acute recurrent pancreatitis were treated at our institution using our recently developed 7Fr plastic stent between Aug. 2013 and Jan. 2018. Results: The stent was placed successfully in all the patients (32/32) and clinical success was achieved in all the patients. Early adverse events occurred in 7 patients (21.8%). Two died of primary disease and 3 were lost to follow-up. The remaining 27 patients were followed up after initial EUS-PD for a median of 23 months (range, 1–43 months). Twenty-one patients required regular stent exchange (3 times; range, 1–12 times). Spontaneous stent dislodgement was observed in 6 patients without any symptoms. Four patients wanted the stent removed after 1 year of the initial intervention. Twelve (44%) patients had regular stent exchange even after 1 year of the initial intervention. Three patients converted to standard transpapillary pancreatic duct stenting by conventional ERCP. Nine (33%) patients had complete stent removal either intentionally or by spontaneous dislodgement without any symptoms. Conclusions: The new plastic stent for EUS-PD allows not only short-term technical success but also long-term clinical success in the majority of patients evaluated in this study.