摘要
目的 研究直肠癌癌旁粘膜的p21、p53蛋白在直肠癌癌旁粘膜的表达，以及癌旁粘膜的距离;探讨p21,p53蛋白在直肠癌组织与癌旁粘膜中表达相关性，探讨癌旁粘膜对于直肠癌安全远端切缘距离及对保肛术的影响。
方法 应用免疫组织化学方法检测34例直肠癌癌组织、癌旁粘膜、正常粘膜中p53、p21蛋白表达。
结果
直肠癌远端扩散有9例，占29.4%，远端扩散距离均在2cm内，其中1cm内7例，超过1cm但在2cm内3例。
34例直肠癌标本其癌组织远端均表现为癌旁粘膜，且为直接延续。在本组标本中，其癌旁粘膜的距离均未超过4cm。
p53在癌旁TM中阳性范围不超出远端4cm肠段,且在3～4cm肠段均为弱阳性表达;p21阳性范围不超出远端2cm肠段;出现p53、p21阳性的粘膜均为移行性改变粘膜,正常对照粘膜p53、p21呈阴性。
p53蛋白在癌组织中表达阳性为20例，阳性率为58.6%；在癌旁组织表达为10例，阳性率为29.3%。同时资料表明两者之间无差异。
p21蛋白在癌组织中表达阳性为21例，阳性率为61.5%；在癌旁组织表达为9例，阳性率为26.4%。同时资料表明两者之间无差异
结论
近年来直肠癌的保肛手术发展迅速，其中一个重要的理论基础就是认为直肠癌远端扩散距离并不是以前认为的5cm。目前国内认为直肠远端切除3cm即可，国外认为可以到2cm甚至是1cm。本组标本也证实了这一观点。本组病理检查表明，远端扩散未超过2cm。
在结、直肠腺癌与正常肠粘膜之间存在癌旁移行粘膜，它是一段过渡性粘膜组织，其组织化学特征表现为粘膜上皮杯状细胞内唾液酸粘蛋白含量增加，硫酸粘蛋白含 量减少或消失，而组织学检查正常，称为癌旁移行粘膜(TM)，表明TM的引出缘于癌旁粘膜组织化学特征方面即粘蛋白的改变。这种移行性改变的组织中没有癌细胞和癌肿浸润灶,在HID-AB 染色中呈Ⅱ级以上唾液酸粘蛋白反应。
在本组标本中，其癌旁粘膜的距离均未超过4cm . 一些研究结果表明癌肿近、远侧移行粘膜范围较离散,差异大,其范围不属于一种围绕均数较集中的分布资料,数据表明癌旁TM长度变动于0～19.5 cm，平均长度为3.4 cm。也有研究报道远侧癌旁TM范围为0.3～9.6 cm，平均范围为(5.3±2.9) cm，其范围分布趋势较离散，未见围绕均数较集中分布现象，癌旁TM长度与肿瘤大小、Dukes分期、分化程度无显著相关性。考虑本组结果与文献不相符合的原因可能与样本例数较少有关。
在癌旁移行粘膜中有着p21,p53蛋白表达。正常组织中存在极微量p21蛋白，并维持细胞正常分化，ki-ras突变激活后可导致p21蛋白过度表达，用常规免疫组化方法可检出［18］。p53是一种重要的抑癌基因。p53基因分野生型和突变型,野生型p53基因即抑癌基因,对细胞增殖有控制作用和负调节作用;突变型p53基因丧失抑癌作用,促进细胞向恶性转化。野生型p53蛋白在细胞内易水解,半衰期仅20～30min,加之含量低,免疫组化技术不易检出;因此免疫组化法检测的p53蛋白是突变型p53蛋白。P21和p53蛋白的表达表明癌旁粘膜具有恶变可能，是一种癌前病变。
在本组资料中p53蛋白在癌组织中表达阳性为20例，阳性率为58.6%；在癌旁组织表达为10例，阳性率为29.3%。同时资料表明两者之间无差异。p21蛋白在癌组织中表达阳性为21例，阳性率为61.5%；在癌
旁组织表达为9例，阳性率为26.4%。同时资料表明两者之间无差异。这种无差异进一步提示我们应当注意癌旁移行粘膜的存在意义。
癌旁移行粘膜作为一种癌前病变，其对吻合口复发的影响不可忽视，在直肠癌根治术中应充分考虑到这一点。尤其对于决定保肛的手术，要充分权衡保留肛门与吻合口复发的关系。直肠癌远端肠管切除长度不够是吻合口复发的重要原因，如何界定合适的远端肠管切除长度，防止吻合口复发，可从两方面考虑：一是界定直肠癌远端扩散距离，手术时完全切除有癌细胞浸润的远端肠段，切除残余病灶，国外学者建议切1～2 cm足够，国内学者仍然认为远端切缘≥3 cm较安全；二是可从组织学粘蛋白改变、癌基因、抑癌基因及其蛋白含量变化等分子病理学水平来界定远端癌旁移行粘膜长度，手术时完全切除这段癌旁移行粘膜。对于分化程度低，病程晚的患者考虑到TM的存在，远端切除不应局限于所谓的2cm或3cm。考虑到当前低位直肠癌的保肛趋势，安全远端切缘距离的界定尤为重要。
Objective: To study the expression of P21 and P53 in the mucosa adjacent to the rectal cancer, and the distance of mucosa adjacent to the rectal cancer. To discuss the relationship of the expression of P21 and P53 between the rectal cancer tissue and the mucosa adjacent to the cancer, and discuss the affection of the mucosa adjacent to the cancer that which distance is safe for the distal edge in rectal cancer dissection.
Method: To examine the expression of P21 and P53 in the body of the rectal cancer and the mucosa adjacent to the cancer, and the relationship between the expression and the change of mucin. The immunohistochemical research help finish the study, and the samples came from the 34 patients who had got dissection for rectal cancer.
Result:
1. It were 9 samples who had had distal diffused, the ratio is 29.4%, the distance of the distal diffusion were all inner 2 cm, in them, 7 inner 1cm, and 3 inner 2cm but beyond 1cm.
2. All 34 samples of tumor body had the same manifestation, they showed the mucosa adjacent to cancer, and they had continuity from the tumor body. In all samples I had studied, the distance of mucosa adjacent to cancer were all inner 4cm.
3. The range of positive P53 in TM adjacent to the cancer was inner 4cm of distal rectum cavity, and they were all weak positive expression in 3-4cm cavity of distal rectum; the range of positive P21 was inner 2cm of distal rectum cavity; the mucosa who expressed positive P21 and P53 were all transitionally changed mucosa, the P21 and P53 were all negative in the contrastive mucosa.
4. There were 20 samples who got P53 positive in the tumor body,
positive rate is 58.6%; and the number of P53 positive in the tissue of the cancer was 10, it is 29.3%. It had no difference between them from data analysis.
5. There were 21 samples who got P21 positive in the tumor body, positive rate is 61.5%; and the number of P21 positive in the tissue of the cancer was 9, it is 26.4%. It had no difference between them from data analysis.
Conclusion:
1. In recently, the anus-reserved dissection for rectal cancer has rapidly developed, one of the brief theoretical basis is that the distance of distal diffused of rectal cancer is not 5cm that people thought before. Now, internal doctors consider that 3cm is enough distance from tumor to distal in rectal cancer, and it is 2cm even 1cm by external doctor,s theory. The result of my study can also confirm this theory, the pathology of the samples showed that it was inner 2cm of distal diffused.
2. It is transitional mucosa adjacent to carcinoma that lied in the place that is between the normal mucosa and the mucosa of colorectal cancer, it is a piece of transmitted mucosa, its histochemical trait is that the content of saliva acid mucin in the caliciform cells increased, and the content of vitriol mucin decreased or disappeared, but the histoexamination had any uncommon, these mucosa ia called transitional mucosa adjacent to the cancer(TM). TM came from the histochemical trait of mucosa adjacent to cancer, that is the change of mucin. The molecularbiology research about TM presented that TM is a piece of transmitted mucosa that is between tumor and normal mucosa. The presentation include the immature epithelial cells、increased mid-stage cells, the thicker mucosa, gland tube stretched and hemorrhage, and it has many branches, the amount of caliciform cells increased, the volume extended, the mucus prosperously secreted. In this tissue, there had no cancer cells and mass,
in HID-AB stain, it presented beyond degree II saliva acid mucosity protein reaction.
3. In our specimens ,the distance of mucosa adjcent to cancer are less 4cm .Some researchs indicate that the range of mucosa migration of proximal and distal of cancer is far separated.It is hard to describe it by a mean.They vary from 0 to 19.5cm ,by a mean of 3.4cm .Also some data is 0.3 to 9.6cm.The variation does not seem to relate to length of TM ,mass ,stage of Dukes , differentiation etc. the possible reason why our results is not m
引文
1 Breen E,Bleday R.Preservation of the anus in the therapy of distalrectalcancers.Surg Clin North Am,1997,77(1):71～83.
2 Renner k,Rosen HR,Novi G,et al.Quality of life after surgery for rectal cancer,Do we still need a permanernt colostomy.Dis colon Rectum,1999;42(9):1160～1169.
3 Heald RJ, Ryall RDH. Recurrence and survival after total mesorectal excision for rectal cancer. Lancet, 1986,45（8）:1479～1786.
4 Heald RJ, Chir M, Karanjia NS. Results of radical surgery for rectal cancer. World J Surg, 1992,16（4）:818～829.
5 Heald RJ, Husband EM, Ryall RDH. The mesorectum in rectal cancer surgery-The clue to pelvic recurrence? Br J Surg, 1992（10）,69:613～620.
6 Havenga K, DeRuiter MC, Enker WE, et al. Anatomical basis of autonomic nerve preserving total mesorectal excision for rectal cancer. Br J Surg,1996,83(3):384～392.
7 董新舒等 低位直肠癌侧方淋巴结清扫的临床意义.中国普外基础与临床杂志2003.10(2):103～105.
8 Miles EW.A method of performing abdominoperineal excision for carcinoma of the rectum and the ferminal portion of the ferminal protion of the pelvic colon.Lancet,1908,2:1812～1813.
9 贾尔民.直肠癌壁内逆向浸润的临床病理学研究(100例分析).肿瘤防
治研究,1983,10(1):40～42.
10 Paty PB,Cohen AM.The role of surgtery and chemoradiation therapy for cancer of the rection[J].Curr Probl Cancer,1999;23(5):233～241.
11 郁宝铭.低位直肠癌的诊治进展.中国实用外科杂志2002，22（1）：34～37.
12 Rlbin KS. Adequate distal margin of resection for adenocarcinoma of the rectum. World J Surg 1992;16(3):463～466.
13 Filipe MI.Value of histochemical reactions for mucosubstances in the diagnosis of certain pathological conditions of the colon cancer. Gut 1969;10:577～590.
14 Sing SN, Frese MB. Abnormal DNA ploidy and proliferative patterns in superficial colonic epithelium adjacent to colorectal cancer.Cancer 1990;66(4):953～959.
15 刘世信，韩洪越，赵丽中.等直肠癌远端切除2厘米是安全的吗？中国肿瘤临床.1997，24(5):343～345.
16 Sing SN, Frese MB. Abnormal DNA ploidy and proliferative patterns in superficial colonic epithelium adjacent to colorectal cancer.Cancer 1990;66(5):953～959.
17 Rlbin KS. Adequate distal margin of resection for adenocarcinoma of the rectum. World J Surg 1992;16(5):463～466.
18 Williams NS,Dixon MF,Johnston D. Reappraisal of the 5 centimeter rule of distal excision for carcinoma of the
rectum.A study of distal intramural spread and of patients survival.Br J Surg 1983;70(5):150～158.
19 Kazuo S,Isomoto H. Distal spread of rectal and optional distal margin of resection for sphincter-preserving surgery.Cancer 1995;76(5):388～392.
20 Kwok SPY,Lau WY,Levng DL,et al. Prospective analysis of the distal margin of clearance in anterior resection for rectal carcinoma. Br J Surg 1996;83(6):969～972.
21 Amdreola S,Leo E,Belli F,et al .Distal intramural spread of adenocarcinoma of the lower third of the rectum treated with total rectal resection and colorectal anastomosis.Dis Colon Rectum 1997;40(6):25～29.
22 许玉成，陈元勇，庄竟，等.直肠癌远侧肠壁浸润规律的探讨. 外科理论和实践 1998；3：148～150.
23 Allen DC,Connllly NS,Biggest JD.High diaminer-alcian blue mucin profiles in benign, premalignant and malignant colorectal disease.Histopathology,1998,13(6):399～411
24 纪小龙,施作霖.诊断免疫组织化学,北京:军事医学科学出版社,1997.61～65.
25 Greaves P.Transitional mucosal and survival in human colorectal cancer.Cancer 1980;46:764～770.
26 王强，王元和，高瀚，等.直肠、乙状结肠癌旁粘膜临床病理学特性及其对前切术后复发的影响.普外临床1995；10:302～304.
27 邓国三，王吉甫.结、直肠癌根治术后吻合口复发与残留移行粘膜的关系.癌症 1993；12：48～49.
28 王强，高潮，王元和，等.Cox回归模型分析癌旁移行粘膜对直肠癌前切术后吻合口复发的影响.中华肿瘤学杂志1991；13：302～304.
29 Haliotis T. Expression of oncogene leads to Down-Regulation of protein kinase C.Int J Cancer 1990;45:1177～1178.
30 杨颖等，用PCR单链多态性快速判别个体检HLA-DP相容性并检出新等位基因，中国临床医学杂志，1994，10（5）：301～309.
31 干月波，蔡心涵，郑树.结直肠癌旁粘膜Ras基因突变的研究.肿瘤防治研究1994；21(5):350～351.
32 彭敦发，林鸿民.结、直肠癌及其癌旁粘膜P53 表达及意义.中国肿瘤临床1996；23(6):217～221.
33 Greaves P , Filipe MI , Branfoot AC. Transitional mucosa and survival in human colorectal cancer [J ] . Cancer , 1980 ; 46 (4)∶764～769
34 郁宝铭.直肠癌保肛手术的现状与展望[J].中国普外基础与临床杂志，2001，8（1）：32～33