The Korean Journal of Pathology 2009; 43: 13-9 DOI: 10.4132/KoreanJPathol.2009.43.1.13 자궁목암종에서 Hypoxia Inducible Factor-1α의발현과 Cyclin A1, Cyclin B1 발현및임상병리학적인자들과의연관성 표주연 1,4 조재호 2 김현기 1 박종필 1 김영태 3 조남훈 1,4 1 연세대학교의과대학병리학교실 The Expression of Hypoxia Inducible Factor-1αand Its Correlation with the Expressions of Cyclin A1 and Cyclin B1 and the Clinicopathologic Factors of Uterine Cervical Carcinoma 2 방사선종양학교실, 3 산부인과학교실 4 BK 21 연세의과학사업단 Ju Yeon Pyo 1,4, Jae Ho Cho 2, Hyunki Kim 1, Jong-pil Park 1, Young Tae Kim 3 and Nam Hoon Cho 1,4 Departments of 1 Pathology, 2 Radiation Oncology, 3 Obstetrics and Gynecology, College of Medicine, Yonsei University, and 4 Brain Korea 21 Project for Medical Science, Seoul, Korea 접수 : 2008 년 7 월 8 일게재승인 : 2008 년 10 월 28 일 책임저자 : 조남훈우 120-752 서울시서대문구신촌동 134 연세대학교의과대학병리학교실전화 : 02-2228-2643 Fax: 02-2227-7939 E-mail: cho1988@yuhs.ac Background : Hypoxia inducible factor-1α(hif-1α) is a transcription factor for various target genes that are involved in adapting cells to hypoxia. It promotes cell proliferation and survival via modulation of such cell cycle regulators such as cyclin A1 and cyclin B1 in response to hypoxia. This is associated with local failure of radiotherapy, which renders a poor prognosis for cervical carcinoma. Methods : Using the tissue histologic sections and a tissue microarray of the archived biopsy and surgical specimens of uterine cervical carcinoma from 57 patients who were treated with radiation therapy alone, we performed immunohistochemical staining for HIF-1αand cyclin A1 and B1 to evaluate the correlations between the expressions of these proteins in tumors and the clinicopathologic parameters associated with the prognosis. Results : The large tumor cell nests and invasive front margins of the tumors showed comparatively intense immunoreactivity of HIF-1α. There was no significant correlation between the HIF-1α, cyclin A1 and cyclin B1 expressions and the clinicopathologic factors. Conclusions : The HIF- 1αexpression showed marked intra-tumoral heterogeneity. The HIF-1αexpression is neither a powerful predictor of resistance to radiotherapy nor is it a poor prognostic marker in cervical carcinoma patients who are treated with radiotherapy. The expressions of cyclin A1 and cyclin B1 are neither independently associated with the response of radiation therapy nor are they associated with the prognostic parameters of uterine cervical carcinoma. Key Words : Cervix cancer; Radiotherapy; Hypoxia inducible factor 1, alpha subunit; Cyclin A; Cyclin B 자궁목암종은최근그상대적빈도가감소하는추세를보이지만한국여성에서발생하는전체악성종양중 5위를차지하고있다. 1 2기말이상의진행된병기의자궁목암종은근치적수술이불가능하거나수술적치료후높은국소재발률을보이기때문에방사선치료가주된치료방법으로사용된다. 고형성종양의종양내저산소상태는방사선치료에대한저항성과치료후의나쁜예후와직접적인연관이있다. 2 자궁목암종과두경부암종에서의방사선치료의효과및예후와관련이있는여러요인들중특히종양내저산소상태는종양의방사선치료에대한저항성을증가시키고, 침윤성과전이력을높이기때문에종양내저산소상태는암종의나쁜생존율과밀접한 연관성이있다는것이다. 2-7 Hypoxia inducible factor 1 (HIF-1) 은조직의저산소상태에대한적응반응에중요한전사인자의하나로, 8 과발현이여러암종의방사선치료에대한저항성을높여생존율을낮춘다. 9 HIF- 1은세포내저산소상태에의하여과발현되어혈관신생 (angiogenesis), 당전달 (glucose transport) 및적혈구생성 (erythropoiesis) 에필요한주요단백질을부호화하는표적유전자의발현을유도한다. HIF-1은산소농도에예민하게반응하는 α소단위와전위 (translocation) 에대해서예민하게반응하는 β소단위로구성된이질이합체 (heterodimer) 이다. HIF-1α는산소농도에예민하게반응하여조직의정상적인산소농도하에서는짧은 13

14 표주연 조재호 김현기외 3 인 시간내에분해되지만저산소상태에서는안정화되고그발현이증가한다. 10 따라서, 종양내저산소상태를반영하는 HIF-1α 의과발현을보이는암종은방사선치료에저항성을보일가능성이크고결국나쁜예후를보일것이라는예측을할수있다. 최근연구들에따르면 HIF-1α를과발현하고있는두경부암및자궁목암종은방사선치료에대한반응이나쁘다고보고하였다. 9,11-13 세포주기는세포내 cyclin 의양과활성도에의하여조절된다. Cyclin은 cyclin-dependent kinase (CDK) 와복합체를형성하여특정세포주기를조절하는인자이다. 이들중 S기와관련된 cyclin A1과 G 2 /M기와관련된 cyclin B1의과발현이자궁목암종의나쁜예후와연관성이있다고보고되었다. 14-16 세포내저산소상태가세포주기에영향을미치는것은 p53 경로를통한세포예정사과정의조절이나 G 1 /S기의이행점 (checkpoint) 을제어함으로써조절된다고알려져있다. 17-20 HIF-1α의과발현과자궁목암종에서의생존율및방사선치료에대한반응성을연구한보고들이있으나, 6,9,12,18,21-24 자궁목암종에서의 HIF-1α발현과세포주기조절인자발현의상관관계에대한연구는아직보고된바없다. 본연구에서는자궁목암종의방사선치료에대한반응성을평가하는척도로써의 HIF-1α 의발현의유용성과, HIF-1α의발현과세포주기조절인자인 cyclin A1 및 cyclin B1 발현의상관관계를알아보고자한다. 아울러 cyclin A1, cyclin B1 및 HIF-1α의발현과자궁목암종의방사선치료와관련한예후인자 25 중병기, 종양의크기와림프선의전이여부및다른임상병리학적인자와의상관관계를확인하여치료반응성및예후예측의지표로서가치가있는지살펴보고자한다. 연구재료 재료와방법 1994년 1월부터 2005년 12월까지자궁목생검결과자궁목암종으로진단받고방사선치료를받은 743명의환자들중병리학적검색이가능한 57예를대상으로하였다. 환자의임상기록지를참고하여진단당시의나이, 종양의조직학적유형, 모양및크기, 안쪽자궁목으로의침윤, 림프절전이여부, FIGO 병기, 추적관찰기간, 재발혹은사망여부, 동반된합병증의유무를조사하였다. 면역조직화학염색및결과판정 10% 중성포르말린에 12시간이상고정후일련의과정을거쳐파라핀에포매하여보관된조직을이용하여 57예중 42예는종양조직에서조직심을취하여 tissue microarray (TMA) 블록으로제작하였고 15예는대표적인파라핀블록을사용하여 면역조직화학염색을시행하였다. 각블록을 4 μm 의두께로박절하여오븐에서파라핀을녹인후자일렌으로파라핀을완전히제거하였다. 에틸알코올로단계적으로함수하였고, 조직절편을 0.3% 과산화수소수에 10분간담근후 ph 6.0의구연산완충액에담가극초단파에 15분간처리하여실온에서식혔다. 일차항체인항 HIF-1α(1:100, ab8366; Abcam, Cambridge, UK), cyclin A1 (1:100, Santa Cruz, CA, USA), cyclin B1 (1: 100, Santa Cruz, CA, USA) 항체를상온에서 30분간반응시킨후, 냉장고에서 12시간배양하였다. ENVION kit (Dako- Cytomation, Glostrup, Denmark) 를이용한 EnVision 항체복합체방법으로면역과산화효소염색을시행하였다. 3,3-diaminobenzidine tetrachloride chromogen (DAB) 으로발색한후헤마톡실린으로대조염색하였다. HIF-1α는종양세포의핵에갈색으로염색되는경우를양성으로판정하여, 염색의정도에따라서전체종양의 10% 미만에서양성반응을나타내는경우를 1+, 10% 이상 50% 미만에서양성반응을나타내는경우는 2+, 50% 이상에서양성반응을나타내는경우는 3+ 로판독하였다. Cyclin A1과 cyclin B1은핵또는세포질에염색되는경우를양성으로판정하고, 종양세포의밀도가높은 3-5개의고배율 ( 400) 시야에서 500개의종양세포중에서양성인세포의수를세어백분율을구하여 30% 미만까지를음성군으로분류하였고, 30% 이상에서염색된경우를양성군으로분류하였다. 통계학적분석 SPSS 프로그램 (SPSS Inc, Chicago, IL, USA, ver.13.0) 을이용하여 HIF-1α의발현과임상적인자인진단당시연령, 종양의조직학적유형, 모양, 크기, 병기, 안쪽자궁목으로의침윤, 합병증유무, 방사선치료의반응사이의연관성을 chi-square 검정또는 Fisher s exact 검정으로분석하였다. HIF-1α 의발현및임상병리학적인자들과생존율과의관계는 Kaplan-Meier method의 log-rank 검정으로단변량분석하였고, Multivariate Cox proportional hazard model을이용하여다변량분석하였다. 생존기간은진단당시날짜로부터자궁목암종으로인한사망일까지를개월로계산하였다. p값이 0.05 이하인경우에한하여통계적으로유의한것으로판정하였다. 결과임상소견환자의연령분포는 31세에서 79세까지였으며, 평균나이는 58.7 세였다. 종양의크기는 1 cm 에서 10 cm 로다양했으며 4 cm 이상은 20예 (35.1%) 였다. 57예중 34예 (59.6%) 는진단당시

자궁목암종에서의 HIF-1α발현 15 FIGO stage가 2기 이상이었으며, 4예(7%)에서 골반임파선전 이가 있었다. 추적 관찰 기간은 14개월에서 108개월이며 평균 추적 관찰 기간은 51.4개월이었다. 방사선 치료 후 55예(96.5%) 에서는 완전 관해되었고, 2예(3.5%)에서 부분 관해되었다. 추 적 관찰 기간 중 5예(8.8%)에서 재발하였으며, 그 중 3예(5.3%) 가 자궁목 및 질에서의 국소 재발이었다. 합병증이 생긴 경우는 모두 18예였다. 조직학적 소견 조직학적 유형은 51예가 편평세포암종이었고, 6예는 샘암종 이었다. 50예에서 종양의 성장 양식은 침윤형이었고 7예는 돌출 형이었다. 편평세포암종 51예 중 44예는 대세포형이었으며, 이 중 14예에서 각화현상을 보였다. 면역조직화학 염색 결과 HIF-1α는 종양 세포의 3%에서 96%까지 발현되었고, 평균 발현율은 42.8±35.7%였다. HIF-1α는 종양 세포뿐만 아니라 혈관내피 세포에서도 핵에 염색되었으며, 기질의 혈관에서는 위 치에 따라서 다양하게 나타났으나 혈관의 직경이 작을수록 더 강하게 염색되는 양상을 보였다. 바깥자궁목의 정상 편평상피 A B C D E F Fig. 1. Immunohistochemical staining for HIF-1αin cervical carcinoma shows variable nuclear expression in tumor cells and blood vessels (A-C). The invasive front margin (D) and large tumor cell nest (E) show slightly prominent nuclear expression, compared with around tumor cells. The endocervical glands do not express HIF-1α(F). A B Fig. 2. Immunohistochemical staining for cyclin A1 (A) and cyclin B1 (B) shows nuclear and cytoplasmic expression in cervical carcinoma.

16 표주연 조재호 김현기외 3 인 세포층에서는 parabasal cell과 intermediate cell에서만염색되었고, 암종에인접해있는자궁목상피내종양 (cervical intraepithelial neoplasia) 및상피내암종의경우대부분의종양세포가 Table 1. Relationship between HIF-1αexpression and clinicopathologic factors in uterine cervical carcinoma Variables Patients number HIF-1αexpression - 1+ 2+ 3+ p- value Total 57 12 5 12 28 Histologic type 0.970 Squamous cell carcinoma 51 10 5 12 24 Adenocarcinoma 6 2 0 0 4 Tumor shape 0.049 Exophytic 7 4 0 1 2 Endophytic 50 8 5 11 26 Tumor size 0.192 <4 cm 37 5 4 9 19 4 cm 20 7 1 3 9 Endocervical extension 0.079 No 51 9 5 10 27 Yes 6 3 0 2 1 FIGO stage 0.449 I-II 54 11 5 10 28 III-IV 3 1 0 2 0 Age 0.228 <60 years 26 4 1 7 14 60 years 31 8 4 5 14 Complication 0.083 No 39 11 3 8 17 Yes 18 1 2 4 11 Reponse to radiotherapy 0.240 CR 55 11 5 11 28 PR 2 1 0 1 0 -, negative; 1+, 1-9%; 2+,10-49%; 3+, 50-100% of tumor cells; CR, complete remission; PR, partial remission. 강하게염색되었다 (Fig. 1A, B). 자궁목의샘암종에서도강하게염색되었다 (Fig. 1C). 종양세포의괴사가동반된경우괴사된종양세포에는염색되지않았으나괴사부위주변의종양세 Table 2. Relationship between cyclin A1, cyclin B1 expression and clinicopathologic factors in uterine cervical carcinoma Variables Patients number cyclin A1 - + p-value cyclin B1 - + p-value Total 57 22 35 27 30 Histologic type 0.548 0.321 Squamous cell 51 19 32 23 28 carcinoma Adenocarcinoma 6 3 3 4 2 Tumor shape 0.564 0.584 Exophytic 7 2 5 4 3 Endophytic 50 20 30 23 27 Tumor size 0.874 0.772 <4 cm 37 14 23 17 20 4 cm 20 8 12 10 10 Endocervical extension 0.781 0.872 No 51 20 31 24 27 Yes 6 2 4 3 3 FIGO stage 0.671 0.460 I-II 54 21 33 25 29 III-IV 3 1 2 2 1 Age 0.601 0.461 <60 years 26 10 16 13 13 60 years 31 12 19 14 17 Complication 0.976 0.789 No 39 15 24 18 21 Yes 18 7 11 9 9 Response to radiotherapy 0.627 0.727 CR 55 21 34 26 29 PR 2 1 1 1 1 -, 0-29% of tumor cells, +, 30% of tumor cells; CR, complete remission; PR, partial remission. 100 100 80 80 Cyclin B1 60 40 Cyclin B1 60 40 20 20 0 R Sq Liner=0.202 0 R Sq Liner=0.188 0 20 40 60 80 100 HIF-1α 0 20 40 60 80 100 Cyclin A1 Fig. 3. Scatter diagram of HIF-1αand cyclin B1 reveals positive linear correlation (correlation coefficient 0.449, p<0.05). Fig. 4. Scatter diagram of cyclin A1 and cyclin B1 reveals positive linear correlation (correlation coefficient 0.48, p<0.05).

자궁목암종에서의 HIF-1α 발현 17 포에서약양성을보였다. 침윤방향에따른위치및종양세포의군집의크기에따라서도다양한염색양상을보였는데침윤성성장양상의종양의침윤부위는주변에비해강하게염색되었고 (Fig. 1D), 종양세포의군집의크기가클수록발현의정도가증가하였다 (Fig. 1E). 정상자궁목샘의세포는염색되지않았으나자궁목샘의비종양성증식이있는부위에서는예비세포 (reserve cell) 에만염색되었다 (Fig. 1F). Cyclin A1은핵과세포질에서발현되었으며 5% 에서 100% 까지다양하였으며, 평균발현율은 41.8±31.8% 였다. Cyclin B1도 cyclin A1과유사하게 3% 에서 100% 까지발현되었으며, 평균은 42.9±6.3% 였다 (Fig. 2). HIF-1α, cyclin A1과 cyclin B1 각인자들간에양의상관관계를보였는데 HIF-1α와 cyclin B1는 0.449의상관계수를보였고 (Fig. 3), cyclin A1과 cyclin B1은 0.434의상관계수를보였다 (Fig. 4). Table 3. Univariate survival analysis of clinical factors and immunohistochemical markers for uterine cervical carcinoma using the Kaplan-Meier method with a log-rank test Variables p-value Clinical factors Age (<60 vs 60 years) 0.215 Histologic type (squamous cell 0.461 carcinoma vs adenocarcinoma) Tumor shape (exophytic vs endophytic) 0.472 Tumor size (<4 cm vs 4 cm) 0.026 Endocervical extension (no vs yes) 0.022 FIGO stage (<IIIA vs IIIA) 0.083 Pelvic node metastasis (no vs yes) 0.194 Complication (no vs yes) 0.094 Response to radiotherapy (CR vs PR) 0.009 Immunohisto- HIF-1α(0 vs <10% vs 10-50% vs 50%) 0.422 chemical Cyclin A1 (<30% vs 30%) 0.310 markers Cyclin B1 (<30% vs 30%) 0.732 CR, complete remission; PR, partial remission. 자궁목암종의임상적, 병리학적인자와면역조직화학염색결과비교 HIF-1α는종양의성장양상이돌출형인경우보다침윤형인경우에서더많이발현되었다 (p=0.049). 그러나다른임상및병리학적인자들과는통계적으로유의한관련성이없었으며 (Table 1), 종양의 cyclin A1 및 cyclin B1의발현정도와도통계적으로유의한관련성은없었다 (Table 2). 자궁목암종환자의생존에영향을미치는예후인자분석 Kaplan-Meier method의 log-rank 검정으로단변량분석을한결과, 종양세포의크기가 4 cm 이상인경우 (p=0.026) 와골반임파선전이가있는경우 (p=0.022) 및방사선치료에부분관해를보이는경우 (p=0.009) 에생존율이낮았다 (Fig. 5). Cyclin Table 4. Cox regression multivariate survival analysis of clinical factors and immunohistochemical markers in uterine cervical carcinoma Disease-free survival Significance (P) 95% CI HIF-1α(0 vs <10% vs 10-50% vs 50%) 0.425 Cyclin A1 (<30% vs 30%) 0.333 Cyclin B1 (<30% vs 30%) 0.770 Age (<60 vs 60 years) 0.283 Histologic type (squamous cell carcinoma 0.545 vs adenocarcinoma) Tumor shape (exophytic vs endophytic) 0.638 Tumor size (<4 cm vs 4 cm) 0.108 Endocervical extension (no vs yes) 0.045 1.037-37.256 6.217 FIGO stage (<IIIA vs IIIA) 0.483 Pelvic node metastasis (no vs yes) 0.499 Complication (no vs yes) 0.082 CI, confidence interval; RR, relative risk. RR 1.0 1.0 Disease-free survival 0.8 0.6 0.4 0.2 p=0.422 HIF-1α 0% <10% 10-49% 50-100 Disease-free survival 0.8 0.6 0.4 0.2 p=0.026 Tumer size <4 cm >4 cm 0.0 0.0 0 20 40 60 80 100 120 Time (months) A 0 20 40 60 80 100 120 Time (months) B Fig. 5. Kaplan-Meier survival curve reveals no statistically significant difference between the prognosis of uterine cervical carcinoma and expression of HIF-1α(A, p=0.422). The survival curve is statistically significant (B, p=0.026) according to tumor size (<4 cm vs 4 cm).

18 표주연 조재호 김현기외 3 인 A1 및 cyclin B1은발현이음성이거나발현율이 30% 미만인경우에생존율이낮은경향을보였지만통계적으로유의하지는않았다 (Table 3). Multivariate Cox proportional hazards model을이용하여다변량분석을한결과, 임상적인자로는안쪽자궁목으로침윤이있는경우에만통계적으로유의한차이가있었고, HIF-1α, cyclin A1 및 cyclin B1의발현정도에따른생존율의차이는유의성이없었다. 고찰소수의연구에따르면종양내저산소상태와관련된 HIF-1α 의발현정도가국소적으로진행된자궁목암종의예후에영향을미친다고보고된바있다. 9 그러나자궁목암종을포함한거의대부분의고형성종양에서 HIF-1α 의발현양상은다양하고이질적이다. 13 Talks 등 24 은면역화학염색, Western blot, in situ hybridization을이용하여여러종류의종양과정상조직에서의 HIF- 1α의발현을분석한결과다른연구에서처럼종양부위에서의 HIF-1α의발현정도와강도는다양하다고보고하였고정상조직에서의발현이종양에비해현저히감소한다는점에서 HIF-1α 의종양의진단적또는치료적지표로서의유의성을제시한바있다. 본연구에서는면역조직화학염색에서 HIF-1α가바깥자궁목의정상중층편평상피와안쪽자궁목원주상피에는염색이되지않았지만인유두종바이러스감염및전암성병변에서는염색되었으며, 암종조직에서는다양한염색양상을보였다. 종양내분포하는혈관의직경이작을수록종양세포의군집이클수록강하게발현되는점, 괴사부위주변의종양세포에서약양성을보인점은 HIF-1α가종양내저산소상태를반영하는결과로판단하였다. 침윤성성장양상을보이는종양의침윤부위가좀더강하게염색되는점도종양세포의침윤과정에서발생할수있는저산소상태를반영하는것으로판단하였다. 서등 26 에따르면자궁목의편평세포암종에서 HIF-1α의발현은 vascular endothelial growth factor (VEGF) 의발현과유의한상관관계를보이며 VEGF의발현은침윤성종양세포와주변의간질세포및염증세포에서뚜렷하였고따라서 HIF-1α의발현은 VEGF의발현증가를통하여종양내맥관형성에도부분적으로기여할것으로판단된다고저자들은보고하였다. 본연구에서도 HIF-1α의발현이침윤성성장을하는종양세포에서더많이발현되는경향을보였다. 그러나, 암종에서의 HIF-1α의발현정도는연구자들마다다소차이를보였다. 또한 HIF-1α의발현과암종의예후및치료에대한반응과의상관관계도저자들마다차이를보였다. Haugland 등 20 은종양내저산소상태가심할수록종양세포의 HIF- 1α발현이증가하지만예후인자로서의통계적인유의성은없다고보고하였다. 서등 26 의연구에서는자궁목편평세포암종 70 예중 19예 (27.1%) 만 HIF-1α를발현하였고이의발현과환자 의연령, FIGO 병기, 골반림프절전이, 미세혈관수와유의한상관관계는없다고하였다. 이에반하여 Bachtiary 21 등은 HIF- 1α의과발현이방사선치료에대한반응성과생존율에나쁜영향을미치는예후인자라고보고하였다. 병기 IB-IVA의 78예를대상으로한 Burri 등 12 연구에의하면암종의 HIF-1α가강하게발현될수록나쁜예후를보인다고 (p=0.01, log-rank) 보고하였다. 이등 27 의연구에서도 57예의자궁목편평세포암종중 46예 (81.7%) 가 HIF-1α를발현하였고, HIF-1α의과발현은높은병기와통계적으로유의한상관관계가있었으며방사선치료후불완전관해를보이는확률및사망률이의미있게높아예후인자로서의의미를보고하였다. 그러나, Mayer 등 23 은38예의자궁목편평세포암종을대상으로한연구에서암종의 HIF-1α의발현이암종내의실제산소농도와는상관이없음을밝힘으로써 HIF-1α의발현은종양의저산소상태를반영하는지표로서의의미가없을뿐만아니라, 예후인자로서의의미도없다고주장하였다. 본연구에서도 HIF-1α 의발현과방사선치료후관해정도또는생존율과의연관성은통계적으로유의하지않았다. 이렇게여러연구의결과들이서로다른것에대해 Haugland 등 20 은 HIF-1α가조직내산소상태의변화에빨리반응하는특성상생검된검체의고정시간이나고정용액의차이에따라 HIF-1α의발현이달라질수있다고지적한바있다. 그리고 HIF-1α의산소농도에따른변화의민감한정도가환자마다다를수있다는점, 한종양에서도부위마다염색의정도와강도가다른점, 이에대한염색의판정의차이, 환자군의자궁목암종의조직학적유형의분포가연구표본마다다른점또한이러한다양한결과의원인으로생각된다. 세포주기관련인자로서자궁목암종에서나쁜예후와관련있다고알려진 cyclin A1과 cyclin B1은본연구에서 HIF-1α 와마찬가지로정상조직에서도발현하였으며종양세포에서도부위마다다양한양상으로발현하였다. 그리고기대했던바와달리염색결과와생존율과는연관성이없다는결과를얻었다. HIF- 1α와 cyclin B1의발현이서로연관성을보인것은 ( 상관계수 = 0.446) 종양의증식이활발한부위일수록저산소상태일가능성이높고따라서 HIF-1α가과발현될것이라는점을유추할수있지만, HIF-1α가세포주기를지연시키는주요한조절인자일것이라는보고 16 도있어추가연구가필요할것으로생각된다. 결론적으로 HIF-1α의발현정도는자궁목암종의침윤성병변내에다양하게발현함으로써종양의저산소상태를반영하는내적인자로서의기능을반영한다고볼수있지만아직은방사선치료에대한반응이나예후를예측하는측도로단정지을수없을것으로판단된다. 참고문헌 1. Shin HR, Jung KW, Won YJ, Park JG. 2002 Annual report of the

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