Objective: Frequent P53 mutations and Ki-ras codon 12 point mutations have been reported in pancreatic cancer. Pancreatic cancer often recurs in the liver and/or lymph nodes shortly after a surgical resection. The purpose of this study is to elucidate the occurrence of microcirculating cancer cells and micrometastasis in pancreatic cancer.
Methods: P53 mutations and Ki-ras codon 12 point mutations were examined in the main tumor, liver, portal vein, and peripheral arterial blood, and para-aortic lymph nodes of patients with pancreatic cancer using molecular examinations.
Results: P53 mutations in the main tumor were present in nine (29%) of 31 patients with pancreatic cancer, whereas a Ki-ras codon 12 point mutation was evident in 18 (62%) of 29 examined patients. The peripheral arterial and portal vein blood and liver were positive for gene abnormalities in one (5%) of 21, in none (0%) of 19, and in one (1%) of 20, respectively. A P53 mutation in the main tumor was evident in none (0%) of seven stage I or II carcinomas and in nine (38%) of 24 stage III or IV cases, whereas a Ki-ras codon 12 point mutation was present in four (67%) of six stage I or II cases and in 14 (61%) of 23 stage III or IV cases. In addition, 15 (71%) of 21 patients with gene abnormalities (Ki-ras codon 12 point and/or p53 mutation) in the main tumor showed lymph node metastasis at surgery, whereas five (42%) of 12 without gene abnormalities did not demonstrate lymph node metastasis. Two (29%) of six patients with gene abnormalities in the main tumor and without metastatic disease at surgery developed liver metastasis within 6 months after surgery, whereas all five (100%) without the gene abnormalities and metastatic disease at surgery did not develop the metastasis, with the sensitivity being 100%, specificity 44%, the predictive value of the positive test 36%, and the predictive value of the negative test 100%. Two patients who had gene abnormalities in the para-aortic lymph node were free from histopathological metastasis and these two patients developed para-aortic lymph node metastasis within 6 months after surgery.
Conclusions: A molecular examination of Ki-ras codon 12 and p53 mutations therefore enables us to predict, to some degree, the occurrence of liver and lymph node metastasis in pancreatic carcinoma.