Impact of orotate phosphoribosyl transferase activity as a predictor of lymph node metastasis in gastric cancer.

Orotate phosphoribosyl transferase (OPRT) is an essential nucleotide metabolic enzyme for cell proliferation and also a key enzyme for conversion of 5-FU to its active form in tumor tissue. The association between tumor OPRT activity and pathophysiological status, including lymph node metastasis [pN+], and the impact of OPRT for predicting pN+ were investigated in gastric cancer. The lymph node status of 73 resectable gastric cancer patients was analyzed preoperatively by computed tomography (CT), ultrasonography and magnetic resonance, and the OPRT activity of collected tumor tissue was measured. Then these data were compared with pathological observation of a surgical lymph node specimen. OPRT activity in the tumor tissue decreased as the depth of invasion increased. An OPRT test demonstrated superior sensitivity and comparable accuracy and sensitivity for predicting pN+, against current imaging diagnoses. Furthermore, the analysis of node negative patients by CT revealed that 80% of false negative patients were retrieved by this OPRT test. Thus, OPRT activity in tumor tissue was a powerful predictor of pN+ in resectable gastric cancer, and the preoperative OPRT test, when it becomes possible, would provide a basis for accurate evaluation of disease status, which is indispensable for the planning of personalized therapy.

Gallbladder reefing for cholelithiasis as a complication of colon cancer.

In an 83-year-old woman presenting with gallstones and a cancer in the sigmoid colon, resection was performed through a median incision, after which the wound was extended, the stones were crushed, and the gallbladder was infolded and sutured (reefed). Even in elderly patients, some treatment for bile stones should be done at abdominal section to avoid future cholecystitis or complications. Reefing is a useful technique that can be done easily from a comparatively narrow field of view.

Usefulness of the perineum pusher in performing rectal procedures.

We invented the Perineum Pusher to prevent excessive extension of the rectum by elevating the bottom of the pelvis. In the treatment of cancers of the middle and lower thirds of the rectum, a clear operative view can be maintained for a long time by using the Perineum Pusher. Consequently, a sphincter-saving rectal resection with coloanal anastomosis can be performed easily and safely. In addition, intraoperative rectal irrigation can be performed using the Perineum Pusher. No complications resulting from the Perineum Pusher have been experienced in 27 rectal cancer patients. As the Perineum Pusher can be used very simply and effectively in sphincter-saving rectal resections with coloanal anastomosis, this new surgical instrument is therefore highly recommended for use when performing various rectal procedures.

Inflammatory polyps in common bile duct caused by T-tube.

We describe two patients who formed inflammatory polyps at the side holes of T-tubes. It seems advisable to remove T-tubes as soon as it is appropriate. New designs and materials may also help avert these lesions.

[Correlation between clinical pathophysiologic factors and expression of orotate phosphoribosyl transferase (OPRT), thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD) in colorectal cancer].

We measured the activity of orotate phosphoribosyl transferase (OPRT), the amount of thymidylate synthase (TS) enzyme, and the activity of dihydropyrimidine dehydrogenase (DPD) for individual tissue types in order to study the contribution of these substances to the effects of the pyrimidine fluoride anticancer drug 5-fluorouracil (5-FU). We also studied the correlation between these 3 enzymes and clinical pathophysiologic characteristics (age, sex, extent of tumor invasion, extent of metastasis to the lymph nodes, lymphatic invasion and the venous invasion of the colorectal wall). Sixty-eight patients with colorectal carcinoma who had undergone surgical resection in our department were studied. There was a significant (p < 0.01) elevation of OPRT activity in the tumor tissue compared with regions of normal tissue. OPRT activity levels in the tumor tissue were lowest in patients with mucinous carcinoma while TS enzyme levels showed the highest activity in tumor tissue in poorly differentiated adenocarcinoma. DPD also showed high activity levels in tumor tissue in poorly differentiated adenocarcinoma and mucinous carcinoma. It is possible that the expression of enzymes with respect to the antitumor effects of 5-FU is a factor contributing to the poor prognosis for patients with poorly differentiated adenocarcinoma and mucinous carcinoma. In the present study of clinical pathophysiologic characteristics, we found that metastasis to the lymph nodes was associated with a significant reduction in the OPRT tumor/normal (T/N) ratio. Our results indicate that it may be possible to predict lymphatic metastasis by determining the T/N ratio for OPRT before surgery.