探討子宮內膜癌中第二型環氧化酶、芳香酶、雌激素與黃體素接受器之表現與臨床病理特徵與存活之相關

Expression of Cyclooxygenase –2, Aromatase, ER and PR and Their Correlation with Clinicopathological Characteristics or Survival in Endometrial Cancer

葛裕民([e-mail])

指導教授 ： 林隆堯

中山醫學大學/醫學院/醫學研究所/碩士(2007年)

https://doi.org/10.6834/CSMU.2007.00064

摘要

子宮內膜癌是歐美國家婦癌的第一位。在臺灣，子宮內膜癌的發生率也有逐漸增加的趨勢。大部份的子宮內膜癌，好發於停經前後。只有不到百分之5發生在40歲之前的婦女。
多數子宮內膜癌的發生與不適當之雌激素暴露有關。它們共同的特徵往往是病人較為年輕、細胞分化較成熟、預後較好。臨床上，應用手術後病理的危險因子做為輔助性放射線治療與化學治療的依據。大部份的子宮內膜癌治癒率極高，然而即使是早期癌症，依然有10%至20%的病人雖經上述的方式治療仍因疾病復發而死亡。因此，我们需要更好的指標給予病人最適當的治療。
近年來，由於分子生物學的進步，發現腫瘤的基因表現、酵素功能與臨床表現、預後評估的多重關係，應用生物標記針對不同病人給與不同治療的觀念，是未來之趨勢。第二型環氧化酶與癌症發生有關，研究發現此酵素會促進細胞增生、抑制細胞程序性的死亡、增加新生血管與黏著分子來促進腫瘤的侵犯與轉移，甚至壓抑宿主的免疫反應。臨床上也發現許多惡性腫瘤細胞有第二型環氧化酶的表現，如子宮頸癌，報告指出與淋巴結轉移、放射線治療失敗有正相關。而在大腸癌的研究上，經由大型的流行病學的研究發現長期使用抗第二型環氧化酶的藥物可有效降低40%至50%的大腸癌死亡率。而早期的研究也發現第二型環氧化酶的表現在子宮內膜增生與子宮內膜癌的組織比正常的子宮內膜來得明顯。因此，第二型環氧化酶在子宮內膜癌的角色就特別值得期待。
而芳香酶活性近來被普偏認為與一些雌激素依賴性腫瘤如子宮內膜異位、子宮肌瘤及乳癌的形成有關。我們先前的研究也發現子宮內膜癌腫瘤部位有芳香酶表現的患者, 其罹病年齡較輕,組織分化較好，顯示芳香酶確實可能在特定的子宮內膜癌族群的腫瘤生成過程中扮演一定的角色。也有研究發現前列腺素會向上調控芳香酶的活性。從另一種與雌激素相關的惡性腫瘤-乳癌研究亦發現，第二型環氧化酶與芳香酶的表現有線性相關，彼此的調控可能是以自泌或旁泌的基轉。這也給予我們探討兩者於子宮內膜癌關聯性的想法。
荷爾蒙接受器也被認為是雌激素刺激細胞增生的重要管道。在許多雌激素依賴性癌症中會過度表現，並與預後有關。
本回顧型計劃是利用免疫組織化學染色的方法研究接受手術之子宮內膜癌患者腫瘤細胞中第二型環氧化酶、芳香酶與荷爾蒙接受器的表現與相關性。並與病人之臨床病理特徵經由統計分析後，找出第二型環氧化酶、芳香酶與荷爾蒙接受器是否是子宮內膜癌病患存活率的獨立預後因子。並進一步探討上述酵素相互作用機轉，評估第二型環氧化酶抑制劑合併傳統治療之可能性。共155位病人納入本實驗，結果顯示荷爾蒙接受器在腫瘤細胞中比第二型環氧化酶與芳香脢有更多的表現。老年人、子宮肌肉層腫瘤細胞侵犯較深、腫瘤細胞分化較差與出現淋巴血管腔侵襲者明顯表現出第二型環氧化酶陽性。而芳香酶之活性則只與淋巴血管腔侵襲有明顯相關性。至於雌激素接受器的表現並沒有與任何一項臨床病理特徵有顯著的相關性，而黃體素接受器的表現，則在年齡小於60歲、FIGO 分期為第一與二期者、子宮內膜狀腺癌者最為強烈。而免疫組織化學染色表現彼此間之相關性，第二型環氧化酶的表現與芳香酶、雌激素接受器、 黃體素接受器的表現沒有強烈的相關性。芳香酶的表現雖然與第二型環氧化酶、黃體素接受器的表現無關，但卻很明顯的與雌激素接受器的表現相關，至於雌激素接受器與黃體素接受器的表現，相關性則很強。在全部存活分析中，單變量存活分析發現到細胞分化的程度是良好的、沒有淋巴血管腔侵襲、子宮肌肉層侵犯的深度少於1/2、沒有淋巴結轉移、組織學型態屬於第一型常見之子宮內膜狀、FIGO的分期越早期以及黃體素接受器的表現呈陽性者，治療的存活率明顯較好。 而多重變異分析顯示只有手術分期與淋巴血管腔侵襲獨立的預後因子。
我們的研究顯示，在子宮內膜癌中，FIGO 分期與淋巴血管腔侵襲的出現是病人存活的獨立預後因子。而第二型環氧化酶 和芳香酶的表現也與淋巴血管顯微侵犯有強烈關係。所以， 在子宮內膜癌的病人經外手科術後若出現淋巴血管顯微侵犯的現象，根據我們的研究結果，可考慮第二型環氧化酶和芳香酶抑制劑，單獨或合併使用，提供進一步調查的理論基礎。當然，這個作用必須由大型臨床試驗來證明。

關鍵字

子宮內膜癌 ； 第二型環氧化酶芳香酶免疫組織化學

並列摘要

In Taiwan, the occurrence of endometrial cancer has been gradually increasing. Most endometrial cancer occurs around or after menopause, and only 5 % of women with this disease are under 40 years of age. It is estimated that there are 10% of stage I and 17 % of stage II patients experience recurrence and eventually die of this disease. Therefore, more detailed understanding of the biological risk factor involved in carcinogenesis of endometrial cancer is critical and provide useful information to select individualized treatment.
The enzyme cyclooxygenase (COX), responsible for the conversion of arachidonic acid to prostaglandins, has drawn much attention. The expression of COX-2 has recently been associated with carcinogenesis. In addition, the expression of COX-2 has also been shown to contribute to proliferation, invasion and metastasis in several solid tumors.
Aromatase, the enzyme system catalyzes estrogen biosynthesis. Our previous study also demonstrated that the endometrial cancer patients with positive aromatase immunohistochemical staining were young and the histological grading was better than those with negative staining. Our results are compatible with the “estrogen- dependent type“ endometrial cancer and these also support the role of aromatase in the pathogenesis of endometrial cancer
In breast cancer, previous study revealed that prostaglandin E2, the main COX-2 product, is known to regulate aromatase gene expression. These significant relationships between the aromatase and cyclooxygenase enzyme systems suggest that autocrine and paracrine mechanisms may be involved in hormone-dependent breast cancer development via growth stimulation from local estrogen biosynthesis. However, in the endometrical cancer, another type of estrogen – dependent tumor, has only little information about the correlation between these enzymes.
The purpose of this study was to assess the immunohistochemical expression of COX-2, aromatase, estrogen and progesterone receptors (ER & PR) from a single institution of surgically-removed uterus in women diagnosed with endometrial cancer. The associations among these expressions and traditional clinical-pathological features and clinical outcomes are also checked.
From 1996 to 2004, there were 155 patients who received treatment for endometrial cancer at our institution. Immunohistochemical analysis was performed on paraffin-embedded sections with using commercially available polyclonal antibody for COX-2 and monoclonal antibodies for aromatase, ER and PR. The associations between target protein expression and clinical-pathological variables were analyzed by Chi-square test or Fisher's exact test. The Kaplan–Meier method was used to calculate overall survival and to generate survival curves using the log-rank test to test for survival differences between groups. Multivariate survival analyses were performed using the Cox regression model with overall survival as the outcome measure.
The majority of patients in this study expressed ER (62%) and PR (54.9%), but not COX-2 (39.4%) and aromatase(34.8%). COX-2 was significantly expressed in groups of elderly women, moderate to poor differentiated tumor cell, positive lymphovascular invasion and deep myometrial invasion. The expression of COX-2 did not show to have a strong correlation with aromatase, ER & PR expression. The only clinicopathological variable strongly associated with aromatase overexpression was lymphovascular invasion. Aromatase expression was significantly associated with ER expression. There was a significant association of ER and PR. A univariate Kaplan-Meier procedure for survival analysis and revealed that advanced FIGO stage, non- endometroid subtype , higher nuclear grade , deeper myometrial invasion, presence of LVSI and pelvic lymph node metastasis and absence of PR expression were shown to be related to poor prognosis. Multivariate analyses show that only FIGO stage and LVSI were independent prognostic factors.
In conclusion, our study show the presence of LVSI in endometrial cancer is a significant and independent prognostic factor of survival. The expression of COX-2 and aromatase was significantly associated with LVSI. Therefore, we provide the rationale for further investigation about the use of COX-2 and aromatase inbibiotrs, combination or alone, in group of patients with endometrial carcinoma diagnosed with LVSI after surgical staging.

並列關鍵字

Endometrial cancer ； cyclooxygenase –2 ； Aromatae ； Immunohistochemistry

參考文獻

〔1〕 FIGO, International Federation of Gynecology and Obstetrics. Annual report on the results of treatment in gynecologic cancer. Int J Gynecol Obstet 1989;28:189-90.

〔2〕 Keys HM, Roberts JA, Brunetto VL, Zaino R J, Spirtos, NM, et al. A phase III trial of surgery with or without adjunctive external pelvic radiation therapy in intermediate risk endometrial adenocarcinoma: a Gynecologic Oncology Group study. Gynecol Oncol 2004;92: 7444–51.

〔3〕 Ferrandina G, Legge F, Ranelletti FO, Zannoni GF, Maggiano N, Evangelisti A, Mancuso S, Scambia G, Lauriola L. Cyclooxygenase-2 expression in endometrial carcinoma: corrorrelation with clinicopathologic parameters and clinical Outcome. Cancer 2002; 95:801-7.

〔4〕 Creasman WT, morrow CP, bundy BN, Homesley HD, Graham JE,heller PB. Surgical pathologic spread patterns of endometrial cancer. Cancer 1987;60(8 Suppl):2035-41.

〔5〕 Liu FS. Molecular carcinogenesis of endometrial cancer. Taiwan J Obstet Gynecol. 2007;46:26-32.