?(Fig.22) Open in a separate window Figure 2 Illustrates the expression of tumor antigen (brown nodular pigment) defined by monoclonal Neo 201 in normal colonocytes examined at the margin of resection in a patient presenting with recurrence anastomotic tumor. Tumor antigens (TAA’s) present in colon cancers, had first been isolated from pooled allogeneic membrane homogenates obtained from operating room specimens.10 These tumor proteins, were fractionated and tested for specificity by delayed cutaneous hypersensitivity in individuals with colorectal cancer as well as healthy volunteers. it was possible to demonstrate the presence of altered cellular activity in existing phenotypically normal appearing colonocytes that were in the process of transforming to malignancy. Eight consecutive patients that had been admitted for evaluation H-Val-Pro-Pro-OH and resection of an anastomotic recurrence post colectomy, were studied with regard to possible etiologic factors. The Rabbit Polyclonal to AL2S7 original margins incorporated into the anastomosis were re-examined by immunohistochemistry employing those monoclonal antibodies (mAbs) designed to target colon tumor antigen. This antigen had previously been shown to be expressed only in colon cancer and not in adjacent normal tissue. In addition, biopsies from margins of resection in five patients free of recurrence following colectomy were also studied along with colon specimens from 50 normal patients, non-demonstrating expression of tumor antigen in the normal appearing colonocytes. In each of the patients who had presented with anastomotic recurrence, normal appearing colonocytes defined by light microscopy and found adjacent to the previously resected primary lesion, expressed tumor antigen. The antigen detected in these colonocytes proved to be identical to antigen expressed in the anastomotic recurrence giving credence to the concept that these normal appearing cells in proximity to the tumor were responsible for the regrowth of tumor in the H-Val-Pro-Pro-OH suture line used to establish continuity of the bowel. Based on the findings of this preliminary retrospective study it is felt that at the time of performing a colectomy for a malignant lesion of the bowel, that it is important that those normal appearing colonocytes adjacent to tumor be evaluated for expression of tumor associated antigen. Excluding such cells from an anastomosis, may help to assure that tumor recurrence will be minimized if not totally eliminated. strong class=”kwd-title” Keywords: Anastomotic recurrence, immunohistochemistry, monoclonal antibodies, colon tumor antigen. Introduction In a small, but well defined number of cases, development of an anastomotic recurrence following colectomy for a malignant lesion will occur. 1. The figures for the incidence of such recurrence have ranged from 10-15 % of those patients so treated. Unfortunately when an anastomotic recurrence is noted H-Val-Pro-Pro-OH within the one to two year period following surgery, end results following re-resection are usually poor. It is also felt that when the margin of resection that can be obtained surgically is suboptimal when there is proximity to the levator ani sphincter at the time of low anterior resection, that the incidence of recurrence is more frequently noted. Speculations as to possible causes for this complication have been numerous 2, 3. Various surgical modifications have as such been introduced, but most have failed to reduce the overall incidence of this complication 4. Based on these results, improved technical issues related to performance of this procedure have been found to be of little or no consequence in reducing this problem 5. Recurrence of tumor in this situation, after investigation of a number of possible issues, now appears to be the result of a H-Val-Pro-Pro-OH failure to define premalignant changes noted histologically in the mucosal field adjacent to the primary H-Val-Pro-Pro-OH lesion. Such cellular changes in normal appearing colonocytes within proximity of the primary bowel lesion take place on a molecular level within the normal appearing colonocytes. These transforming cells may inadvertently be incorporated into the suture line used for establishing bowel continuity and be the root cause of the anastomotic recurrence 6. Method of Evaluation Eight cases of consecutive anastomotic recurrence following resection of the colon for adenocarcinoma were evaluated for factors that resulted in the appearance of a local suture line recurrence. In each case, the margins adjacent to the resected primary tumor had been initially examined and found free of dysplastic or atypical cells histologically. These same margins were re-examined after the patient presented with recurrent tumor. In these patients the mucosal cells adjacent to the site of the primary lesion were checked for the expression of tumor antigen and when noted, suggested that malignant transformation was an ongoing process within these cells and that incorporating such cells in the planned suture line was directly responsible for the observed recurrence. In.