• Title/Summary/Keyword: 항암제

Search Result 1,017, Processing Time 0.023 seconds

Comparison of Concurrent Chemoradiotherapy with Conventional Radiotherapy in Advanced Non-smal Cell Lung Cancer (진행된 비소세포 폐암 환자에서 Concurrent Chemoradiotherapy와 Conventional Radiotherapy의 비교)

  • Kim, Hui-Jung;Lee, Dong-Soo;Song, So-Hyang;Jung, Su-Mi;Kim, Young-Kyoon;Yoon, Se-Chul;Moon, Hwa-Sik;Song, Jeong-Sup;Park, Sung-Hak
    • Tuberculosis and Respiratory Diseases
    • /
    • v.44 no.3
    • /
    • pp.493-504
    • /
    • 1997
  • Background : Non-small cell lung cancer is one of the most frequent cause of death due to cancer in men, and its incidence among women is rapidly increasing. Although there has been a recent surge of interest in combined modality therapy for stageIII non-small cell lung cancer(NSCLC), the optimal treatment is still not well established. Thoracic irradiation has long been the gold standard for locally advanced unresectable NSCLC. However, although conventional radiotherapy(XRT) can palliate symptom and improve local control of disease, it has at most only a modest effect on survival. Recently, cisplatin(cis-diamminedichloroplatinum) has been reported to enhance the cell-killing effect of radiation For patients with unresectable NSCLC, cisplatin-based concurrent chemoradiotherapy(CCRT) had the advantage of therapeutic response over XRT alone and therapeutic side effect more commonly occurred in CCRT group in EORTC(European Organization for Research and Treatment of Cancer) and other trials. Objectives : We compared therapeutic response, compliance, and side effects between CCRT and XRT in patients with advanced NSCLC. Patients and Method : Thirty patients with biopsy-proven inoperable NSCLC were randomized to one of two treatment arms. Arm A consisted of XRT, radiotherapy for 4~6 weeks(1.8 Gy given 20~33 times, in five fractions a week), and arm B consisted of CCRT, radiotherapy for 2 weeks(3 Gy given to times, in five fractions a week), followed by 3 week rest period and then radiotherapy 2 more weeks(2.5 Gy given 10 times, in five fractions a week), combined with 6mg cisplatin per square meter, given daily before radiotherapy. We evaluate therapeutic response, compliance, change of performance status, side effects, and radiation pneumonitis by using the author's made scoring system. Results : There was no significant difference in therapeutic response and compliance. But there was a significantly lower laboratory complication and radiation pneumonitis in CCRT group (p < 0.05). There's significant negative correlation between stage and therapeutic response score in both groups(R=0.353, p < 0.05) In both groups, patients with squamous cell carcinoma had a tendency to higher therapeutic response score than those with adenocarcinoma. Conclusion : There was no difference between CCRT and XRT in respect to therapeutic response and compliance. But CCRT had a advantage of decreased side effects.

  • PDF

Apoptotic Cell Death by Pectenotoxin-2 in p53-Deficient Human Hepatocellular Carcinoma Cells (종양억제유전자 p53 결손 인체간암세포에서 Pectenotoxin-2에 의한 Apoptosis 유도)

  • Shin, Dong-Yeok;Kim, Gi-Young;Choi, Byung-Tae;Kang, Ho-Sung;Jung, Jee-H.;Choi, Yung-Hyun
    • Journal of Life Science
    • /
    • v.17 no.10
    • /
    • pp.1447-1451
    • /
    • 2007
  • Through the screening of marine natural compounds that inhibit cancer cell proliferation, we previously reported that pectenotoxin-2 (PTX-2) isolated from marine sponges exhibits selective cytotoxicity against several cell lines in p53-deficient tumor cells compared to those with functional p53. However, the molecular mechanisms of its anti-proliferative action on malignant cell growth are not completely known. To further explore the mechanisms of its anti-cancer activity and to test whether the status of p53 in liver cancer cells correlates with their chemo-sensitivities to PTX-2, we used two well-known hepatocarcinoma cell lines, p53-deficient Hep3B and p53-wild type HepG2. We have demonstrated that PTX-2 markedly inhibits Hep3B cell growth and induces apoptosis whereas HepG2 cells are much more resistant to PTX-2 suggesting that PTX-2 seems to act by p53-independent cytotoxic mechanism. The apoptosis induced by PTX-2 in Hep3B cells was associated with the modulation of DNA fragmentation factor (DFF) family proteins, up-regulation of pro-apoptotic Bcl-2 family members such as Bax and Bcl-xS and activation of caspases (caspase-3, -8 and -9). Blockade of the caspase-3 activity by caspase-3 inhibitor, z-DEVD-fmk, prevented the PTX-2-induced growth inhibition in Hep3B cells. Moreover, treatment with PTX-2 also induced phosphorylation of AKT and extracellular-signal regulating kinase (ERK), but not c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MARK). Specific inhibitors of PI3K inhibitor (LY294002) and ERK1/2 inhibitor (PD98059) significantly blocks PTX-2-induced-anti-proliferative effects, whereas a JNK inhibitor (SP600125) and a p38 MAPK inhibitor (SB203580) have no significant effects demonstrating that the pro-apoptotic effect of PTX-2 mediated through activation of AKT and ERK signal pathway in Hep3B cells.

Enhancement of Sensitivity of Human Lung Cancer Cell Line to TRAIL and Gefitinib by IGF-1R Blockade (폐암세포주에서 IGF-1R 억제를 이용한 TRAIL 및 gefitinib에 대한 감수성 증가를 위한 연구)

  • Lee, Yoon-Jin;Park, Mi-Young;Kang, Young-Ae;Kwon, Sung-Youn;Yoon, Ho-Il;Lee, Jae-Ho;Lee, Choon-Taek
    • Tuberculosis and Respiratory Diseases
    • /
    • v.63 no.1
    • /
    • pp.42-51
    • /
    • 2007
  • Background: TRAIL is a cytokine that selectively induces apoptosis in various cancer cell lines. Gefitinib is new targeted drug applied in lung cancer that selectively inhibits EGFR tyrosine kinase. However, lung cancers have shown an initial or acquired resistance to these drugs. This study examined the effect of IGF-1R and its blockade on enhancing the sensitivity of lung cancer cell lines to TRAIL and gefitinib. Methods: Two lung cancer cell lines were used in this study. NCI H460 is very sensitive to TRAIL and gefitinib. On the other hand, A549 shows moderate resistance to TRAIL and gefitinib. The IGF-1R blockade was performed using adenoviruses expressing the dominant negative IGF-1R and shRNA to IGF-1R and AG1024 (IGF-1R tyrosine kinase inhibitor). Results: The adenovirus expressing dominant negative IGF-1R(950st) induced the increased expression of defective IGF-1R on the lung cancer cell surface, and the adenovirus-shIGF-1R effectively decreased the level of IGF-1R expression on cell surface. The genetic blockade of IGF-1R by the adenovirus-dnIGF-1R and AG1024 increased the sensitivity of A549 cells to TRAIL. The reduction of IGF-1R by transduction with ad-shIGF-1R also increased the sensitivity of the A549 cells to gefitinib. Conclusion: The blockade of IGF-1R through various mechanisms increased the sensitivity of the lung cancer cell line that was resistant to TRAIL and gefitinib. However, further studies using other cell lines showing acquired resistance as well as in vivo animal experiments will be needed.

Efficacy of Small Bowel Displacement System in Post-Operative Pelvic Radiation Therapy of Rectal Cancer (소장 용적 측정을 통한 직장암의 수술 후 방사선치료 시 사용하는 소장 전위 장치(Small Bowel Displacement System : SBDS) 의 효용성 검토)

  • Ahn Yong Chan;Lim Do Hoon;Kim Moon Kyung;Wu Hong Gyun;Kim Dae Yong;Huh Seung Jae
    • Radiation Oncology Journal
    • /
    • v.16 no.1
    • /
    • pp.63-69
    • /
    • 1998
  • Purpose : This study is to evaluate the efficacy of small bowel displacement system(SBDS) in post-operative pelvic radiation therapy(RT) of rectal cancer patients by measurement of small bowel volume included in the radiation fields receiving therapeutic dose. Materials and Method : Ten consecutive new rectal cancer patients referred to the department of Radiation Oncology of Samsung Medical Center in May of 1997 were included in this study. All patients were asked to drink $Castrographin^(R)$ before simulation and were laid prone for conventional simulation and CT scans with and without SBDS. The volume of opacified small bowel on CT scans, which was to be included in the radiation fields receiving therapeutic dose, was measured using Picture archiving and communication system (PACS). Results : The average small bowel volumes with and without SBDS were 176.0ml(5.2-415.6ml) and 185.1ml(54.5-434.2ml), respectively The changes of small bowel volume with SBDS compared to those without SBDS were more than $10\%$ decrease in three, less than 10% decrease in two, less than $10\%$ increase in three, and more than $10\%$ increase in two patients. Conclusion : No significant advantage of using SBDS in post-operative pelvic RT for rectal cancer patients has been shown by small bowel volume measurement using CT scan considering additional effort and time needed for simulation and treatment setup.

  • PDF

Immunohistochemical Study to Evaluate the Prognostic Significance of Four Biomolecular Markers in Radiotherapy of Nasopharyngeal Carcinoma (방사선 치료를 받은 코인두암의 생체분자적 예후 인자를 찾기 위한 면역조직화학염색 연구)

  • Kim, Yeon-Joo;Lee, Seung-Hee;Wu, Hong-Gyun;Go, Heoun-Jeong;Jeon, Yoon-Kyung
    • Radiation Oncology Journal
    • /
    • v.28 no.2
    • /
    • pp.57-63
    • /
    • 2010
  • Purpose: We performed an immunohistochemical study with pre-treatment biopsy specimens to evaluate the prognostic significance of four biomolecular markers which can be used as a predictive assay for radiotherapy (RT) treatment of nasopharyngeal carcinoma (NPC). Materials and Methods: From January 1998 through December 2006, 68 patients were histologically diagnosed as non-metastatic NPC and treated by RT. Only 38 patients had the paraffin block for the immunohistochemical study. Thirty-one patients had undifferentiated carcinoma and 7 patients had squamous cell carcinoma. Thirtytwo patients (84%) had advanced stage NPC (2002 AJCC Stage III~IV). Immunohistochemical staining was performed for Met, COX-2, nm23-H1, and epidermal growth factor receptor (EGFR) expression using routine methods. Results: The median follow-up time was 30 months (range, 11 to 83 months) for all patients, and 39 months (range, 19 to 83 months) for surviving patients. The 5-year overall survival (OS) rate of the patients with high Met extent (${\geq}50%$) was significantly lower than that of the patients with low Met extent (48% vs. 84%, p=0.02). In addition, Met extent was also a significant prognostic factor in multivariate analysis (p=0.01). No correlation was observed between Met extent and T stage, N stage, stage group, gender, age, and the response to chemotherapy or RT. Met extent showed moderate correlation with COX-2 expression (Pearson coefficient 0.496, p<0.01), but COX-2 expression did not affect OS. Neither nm23-H1 or EGFR expression was a prognostic factor for OS in this study. Conclusion: High Met extent (${\geq}50%$) might be an independent prognostic factor that predicts poor OS in NPC treated with RT.

Evaluation of Patient Radiation Doses Using DAP Meter in Interventional Radiology Procedures (인터벤션 시술 시 면적선량계를 이용한 환자 방사선 선량 평가)

  • Kang, Byung-Sam;Yoon, Yong-Su
    • Journal of radiological science and technology
    • /
    • v.40 no.1
    • /
    • pp.27-34
    • /
    • 2017
  • The author investigated interventional radiology patient doses in several other countries, assessed accuracy of DAP meters embedded in intervention equipments in domestic country, conducted measurement of patient doses for 13 major interventional procedures with use of Dose Area Product(DAP) meters from 23 hospitals in Korea, and referred to 8,415 cases of domestic data related to interventional procedures by radiation exposure after evaluation the actual effectives of dose reduction variables through phantom test. Finally, dose reference level for major interventional procedures was suggested. In this study, guidelines for patient doses were $237.7Gy{\cdot}cm^2$ in TACE, $17.3Gy{\cdot}cm^2$ in AVF, $114.1Gy{\cdot}cm^2$ in LE PTA & STENT, $188.5Gy{\cdot}cm^2$ in TFCA, $383.5Gy{\cdot}cm^2$ in Aneurysm Coil, $64.6Gy{\cdot}cm^2$ in PTBD, $64.6Gy{\cdot}cm^2$ in Biliary Stent, $22.4Gy{\cdot}cm^2$ in PCN, $4.3Gy{\cdot}cm^2$ in Hickman, $2.8Gy{\cdot}cm^2$ in Chemo-port, $4.4Gy{\cdot}cm^2$ in Perm-Cather, $17.1Gy{\cdot}cm^2$ in PCD, and $357.9Gy{\cdot}cm^2$ in Vis, EMB. Dose referenece level acquired in this study is considered to be able to use as minimal guidelines for reducing patient dose in the interventional radiology procedures. For the changes and advances of materials and development of equipments and procedures in the interventional radiology procedures, further studies and monitorings are needed on dose reference level Korean DAP dose conversion factor for the domestic procedures.

Results of Radiation Therapy for Carcinoma of the Uterine Cervix (자궁경부암의 방사선치료 성적)

  • Lee Kyung-Ja
    • Radiation Oncology Journal
    • /
    • v.13 no.4
    • /
    • pp.359-368
    • /
    • 1995
  • Purpose : This is a retrospective analysis for pattern of failure, survival rate and prognostic factors of 114 patients with histologically proven invasive cancer of the uterine cervix treated with definitive irradiation. Materials and Methods : One hundred fourteen patients with invasive carcinoma of the cervix were treated with a combination of intracavitary irradiation using Fletcher-Suit applicator and external beam irradiation by 6MV X-ray at the Ewha Womans University Hospital between March 1982 and Mar 1990. The median age was 53 years(range:30-77 years). FIGO stage distribution was 19 for IB, 23 for IIA, 42 for IIB, 12 for IIIA and 18 for IIIB. Summation dose of external beam and intracavitary irradiation to point A was 80-90 Gy(median:8580 cGy) in early stage(IB-IIA) and 85-100 Gy(median:8850 cGy) in advanced stage(IIB-IIIB). Kaplan-Meier method was used to estimate the survival rate and multivariate analysis for progrostic factors was performed using the Log likelihood for Weibull Results : The pelvic failure rates by stage were $10.5{\%}$ for IB. $8.7{\%}$ for IIA, $23.8{\%}$ for IIB, $50.0{\%}$ for IIIA and $38.9{\%}$ for IIIB. The rate of distant metastasis by stage were $0{\%}$ for IB, $8.7{\%}$ for IIA, $4.8{\%}$ for IIB. $0{\%}$ for IIIA and $11.1{\%}$ for IIIB. The time of failure was from 3 to 50 months and with median of 15 months after completion of radiation therapy. There was no significant coorelation between dose to point A($\leq$90 Gy vs >90 Gy) and pelvic tumor control(P>0.05). Incidence rates of grade 2 rectal and bladder complications were $3.5{\%}$(4/114) and $7{\%}$(8/114), respectively and 1 patient had sigmoid colon obstruction and 1 patient had severe cystitis. Overall 5-year survival rate was $70.5{\%}$ and disease-free survival rate was $53.6{\%}$. Overall 5-year survival rate by stage was $100{\%}$ for IB, $76.9{\%}$ for IIA, $77.6{\%}$ for IIB $87.5{\%}$ for IIIA and $69.1{\%}$ for IIIB. Five-rear disease-free survival rate by stage was $81.3{\%}$ for IB, $67.9{\%}$ for IIA, $46.8{\%}$ for IIB, $45.4{\%}$ for IIIA and $34.4{\%}$ for IIIB. The prognostic factors for disease-free survival rate by multivariate analysis was performance status(p= 0.0063) and response rate after completion of radiation therapy(p= 0.0026) but stage, age and radiation dose to point A were not siginificant. Conclusion : The result of radiation therapy for early stage of the uterine cervix cancer was relatively good but local control rate and survival rate in advanced stage were poor inspite of high dose irradiation to point A above 90 Gy. Prospective randomized studies are recommended to establish optimal tumor doses for various stages and volume of carcinoma of uterine cervix, And ajuvant chemotherapy or radiation-sensitizing agents must be considered to increase the pelvic control and survival rate in advanced cancer of uterine cervix.

  • PDF

The Results of Curative Radiotherapy for the Uterine Cervical Cancer (자궁경부암의 근치적 방사선치료 성적)

  • Kim, Hyoung-Jin;Kim, Jung-Soo;Kwon, Hyoung-Cheol;Kim, Jin-Kee;Oh, Byung-Chan
    • Radiation Oncology Journal
    • /
    • v.14 no.3
    • /
    • pp.191-199
    • /
    • 1996
  • Purpose : To evaluate 5-year survival rate, patterns of failure and complications of cervical cancer treatment, fifty nine patients treated by curative radiotherapy for the uterine cervical cancer were analyzed retrospectively. Materials and Methods : From March 1986 to May 1990, fifty nine patients with histologically proven uterine cervical cancer were analyzed. According to FIGO stage, there were 2 patients ($3.4\%$) in stage Ib, 2 patients ($3.4\%$) in stage IIa, 31 patients ($52.5\%$) in stage IIb, 15 patients ($25.4\%$) in stage IIIb, 9 patients ($15.3\%$) in stage IV. External RT was per formed by 6 MVLINAC with daily 1.8 Gy, 5 times per week and followed by ICR. A point dose of ICR was calculated to 30-43.66 Gy (median: 34.6 Gy). These techniques delivered total A Point dose of 80.4 to 109.8 Gy (median: 85 Gy). Patients had been followed up from 2 to 110 months (median: 61 months) Results : The overall 5-year survival rate & disease free survival rate were $55.9\%$ and $55.0\%$ respectively. According to FIGO stage, the 5-year survival rate for less than IIa, IIb, IIIb, IV were $75.0\%$, $74.8\%$, $26.7\%$, $33.3\%$, respectively. In univariate analysis, the 5-year survival rate for stage IIb and below versus stage IIIa and above revealed $74.8\%$, $29.2\%$ respectively (P<0.005). According to the hemoglobin level during RT, the 5-rear survival rate of was $73.3\%$ for patients with Hg 10 gm/dL or higher, in contrast to $0\%$ for those with lower than 10 gm/dL (p<0.005). In 18 patients with nonbulky tumor (<5cm), the 5-year survival rates were $71.8\%$. The 5-rear survival rates for 18 patients with 5 cm or greater in tumor diameter were $22.2\%$ (p<0.005). The 5-year survival rate for Patient age of above 50 years and below were $65.3\%$ $34.2\%$ respectively (p<0.05). ECOG performance status. pathologic finding, total dose, total treatment time were not statistically significant factors. The significant prognostic factors affecting overall 5-year survival rate by multivariate analysis showed the hemoglobin level during RT (P=0.0001), tumor size (p=0.0390), FIGO stage (p=0.0468). Total recurrence rate was $23.7\%$ local failure $15.2\%$ (9/59), distant metastasis $6.8\%$ (4/59), local and distant metastasis $1.7\%$ (1/59). According to the RTOG/EORTC Soma Scales, the late complication rate was $23.8\%$ (14/59) The late complication rate of colorectum and genitourinary tract were $15.3\%$ (9/59), $8.5\%$ (5/59), respectively: 10 patients ($17.0\%$) were grade 2, 3 Patients ($5.1\%$) were grade 3 and one patient ($1.7\%$) was grade 4. The late complications were radiation proctitis, rectal bleeding, radiation colitis, diarrhea and radiation cystitis in decreasing order. Conclusion : For improvement of therapeutic results, prospective randomized trials are recomended to discover new prognostic factors and more aggressive radiation therapeutic methods are needed for poor prognostic patients. The adjuvant chemotherapy or radiation-sensitizing agents must be considered to inhibit regional and distant metastasis.

  • PDF

The Effects of Autologous Blood Pleurodesis in the Pneumothorax with Persistent Air Leak (지속성 기흉에서 자가혈액을 이용한 흉막유착술의 효과)

  • Yoon, Su-Mi;Shin, Sung-Joon;Kim, Young-Chan;Shon, Jang-Won;Yang, Seok-Chul;Yoon, Ho-Joo;Shin, Dong-Ho;Chung, Won-Sang;Park, Sung-Soo
    • Tuberculosis and Respiratory Diseases
    • /
    • v.49 no.6
    • /
    • pp.724-732
    • /
    • 2000
  • Background : In patients with severe chronic lung diseases even a small pneumothorax can result in life-threatening respiratory distress. It is important to treat the attack by chest tube drainage until the lung expands. Pneumothorax with a persistent air leak that does not resolve under prolonged tube thoracostomy suction is usually treated by open operation to excise or oversew a bulla or cluster of blebs to stop the air leak. Pleurodesis by the instillation of chemical agents is used for the patient who has persistent air leak and is not good candidate for surgical treatment. When the primary trial of pleurodesis with common agent fails, it is uncertain which agent should be used f or stopping the air leak by pleurodesis. It is well known that inappropriate drainage of hemothorax results in severe pleural adhesion and thickening. Based on this idea, some reports described a successful treatment with autologous blood instillation for pneumothorax patients with or without residual pleural space. We tried pleurodesis with autologous bood for pneumothorax with persistent air leak and then we evaluated the efficacy and safety. Methods : Fifteen patients who had persistent air leak in the pneumothorax complicated from the severe chronic lung disease were enrolled. They were not good candidates for surgical treatment and doxycycline pleurodesis failed to stop up their air leaks. We used a mixture of autologous blood and 50% dextrose for pleurodesis. Effect and complications were assessed by clinical out∞me, chest radiography and pulmonary function tests. Results : The mean duration of air leak was 18.4${\pm}$6.16 days before ABP (autologous blood and dextrose pleurodesis) and $5.2{\pm}1.68$ days after ABP. The mean severity of pain was $2.3{\pm}0.70$ for DP(doxycycline pleurodesis) and $1.7{\pm}0.59$ for ABDP (p<0.05). There was no other complication except mild fever. Pleural adhesion grade was a mean of $0.6{\pm}0.63$. The mean dyspnea scale was $1.7{\pm}0.46$ before pneumothrax and $2.0{\pm}0.59$ after ABDP (p>0.05). The mean $FEV_1$ was $1.47{\pm}1.01$ before pneumothorax and $1.44{\pm}1.00$ after ABDP (p>0.05). Except in 1 patient, 14 patients had no recurrent pneumothorax. Conclusion : Autologous blood pleurodesis (ABP) was successful for treatment of persistent air leak in the pneumothorax. It was easy and inexpensive and involved less pain than doxycycline pleurodesis. It did not cause complications and severe pleural adhesion. We report that ABP can be considered as a useful treatment for persistent air leak in the pneumothorax complicated from the severe chronic lung disease.

  • PDF

암의 발생기작

  • 임영희
    • Proceedings of the Korean Journal of Food and Nutrition Conference
    • /
    • 1997.06b
    • /
    • pp.8-10
    • /
    • 1997
  • 종양은 아직 그 발생 원인과 기작이 정확히 밝혀져 있지 않으므로 정확한 정의를 내리는 것은 어려우나 일반적으로 종양이란 정상 세포가 갖고 있는 세포 분열의 특이성을 상실하여 일어나는 조직의 자율적인 과잉 성장을 말한다. 이와 같은 세포의 비정상적인 증식에 의한 종양을 임상 및 병리 형태학적으로 양서 종양과 악성종양으로 분류한다. 양성 종양을 일으키는 종양 세포는 정상 세포와 비슷할 뿐 아니라 그 주변 세포들과 확실한 경계를 이루고 있으며 증식도 느리며 다른 부위로의 전이가 없다. 이에 반해 악성종양은 일반적으로 증식도 빠르고 이형의 세포로서 주변의 조직으로 확산, 전이될 뿐만 아니라 최종적으로 숙주인 개체를 사망시킨다. 악성종양은 다시 상피 조직에서 유례한 암, 비상피 조직에서 유래된 육종, 백혈구에서 유래된 백혈병 등으로 구별하지만 그의 본질은 거의 같으며 모든 악성종양은 통속적으로 암이라고 불리운다. 종양의 발생원인으로 크게 3가지로 나눌 수 있는데 화학물질, 바이러스 및 유전적 요인에 의한 것으로 알려졌다. 최초의 발암물질로 알려진 benzopyrene에 의한 발암 등 연구에 의해 화학적 발암원들은 직접 발암 물질로 작용하는 것이 아니라, 일단 체내에서 대사된 후 이들 대사 산물일 DNA 등에 작용함으로써 발암이 유도 되는 것으로 밝혀졌다. 이와 같이 화학적 변화를 거친 후에야 DNA에 영향을 미치는 것외에 다른 화학물질들은 또 다른 기작을 통해 암을 유발하는데 쥐의 피부에 benzopyrene을 한 번 처리하면 암을 유발하지 않으나 여기에 phorbol ester를 처리하면 높은 빈도로 암이 형성된다. 여기서 benzopyrene과 같이 세포의 DNA에 돌연변이를 일으키는 작용을 하는 발암물질을 발암개시제라 하고 phorbol ester처럼 그 자체로는 발암능이 없으나 발암개시제에 노출된 세포에 영향을 미쳐 발암능을 크게 강화시켜 주는 것을 발암촉진제라고 한다. 암은 세포증식 제어계에 DNA가 이상을 일으킨 현상을 말하는 데 이와 같은 DNA의 변형된 유전정보에 의해 암과 관련된 단백질을 합성하므로 이 DNA를 암유전자라 부르며 바이러스에서 유래된 것을 V-one 그리고 세포에서 유래된 것을 c-one이라 한다. 암유전자는 본래 암을 형성하기 위한 것이 아니라 증식제어 유전자로서 변이나 비정상으로 활성화 됨으로써 암을 유발시키므로 proto-oncogene이라 부른다. 또한 고등동물의 유전자 중에는 세포성장을 억제하는 유전자들이 있으며 이들은 세포의 성장 생존 분화를 조절하는 것으로 생각되고 있다. 따라서 이들 유전자는 세포의 암변형을 억제하는 기능을 가지고 있다. 이들 유전자의 이상으로 세포성장 억제기능이 상실되면 세포의 과잉 성장이 초래되면 결과적으로 암으로 유발하는 것으로 추측되고 있다. 최근의 연구에 의하면 암세포에서 암억제 유전자의 이상과 암유전자의 활성화가 함께 발견 되면서 정상세포가 암으로 변형되는 과정에는 암억제 유전자의 이상과 암유전자의 활성화가 동시에 관여한 가능성이 높은 것으로 알려져 있다. 정상 세포가 암을 유발하기 위해서는 발암의 다단계설에서와 같이 여러 단계의 변과가 필요한데 여러 가지 요인에 의해 정상세포의 염색체가 변화되어 정상세포들이 가지고 있는 세포분열의 특이성을 상실하고 증식이 빠르고 저항력이 강한 세포가 선택 되어지고 비정상 서ㅔ포으 과잉 분여러에 의해 종양이 형성되며 이어서 혈관의 신생을 촉진하는 맥관형성, 전이 등이 과정을 거쳐 신체의 다른 부위로 전이된다. 20세기 초까지는 암은 노화와 함께 자연발생적으로 일어나는 피할 수 없는 질병으로 여겨졌으며 그 치료도 조기에 발견된 암환자에게 외과적인 치료를 하는 것이 최선의 방법 이었다. 그러나 현재에는 암환자의 80% 이상이 환경적 요인에 의해 암이 발생 된다고 믿어지고 있다. 과거 치료에 중점을 둔 것에서 점차 예방의 가능성과 그 방법의 모색에 관심을 갖게 되었으며 치료적인 면에서도 외과적 수술 이외에 방사선 치료, 항암제의 투여 등 약물요법, 면역요법의 이용 이외에 더 나아가 gene theraph 및 tumor vaccines 개발에 대한 관심도 증가되고 있다. 국제암연구협회에서는 인간에게 발암이 가능한 물질의 종류를 정기적으로 발표하고 있는데 지금까지 발암 가능성이 높다고 널리 알려진 위험요인을 크게 나누어 보면 다음과 같다. 흡연, 음주, 식이요인, 호르몬 및 기타 요인으로 약물, 자외선 등을 들 수 있는데 현재까지 이들 요인에 의한 발암 기작이 완전히 규명된 것은 아니지만 이들에 의한 발암의 확률이 높다는 것은 사실이므로 이 위험요인에 노출되는 것을 방지함으로써 암발생을 예방할 수 있을 것이다. 암발생의 예방법으로는 암발생 자체를 예방하는 것과 이미 발생한 암환자를 조기 발견하고 치료하는 방법이 있을 수 있다. 현재까지의 여러 연구 결과들을 보면 유전적인 요인을 제외한 대부분의 발암 위험인자들은 개개인의 생활습관과 밀접히 관련되어 있음을 알 수 있다. 이를 바탕으로 1992년 대한 암협회에서는 '암 예방 14개 권장 사항'을 발표하여 국민 홍보활동을 하고 있는데 그 내용의 반 이상이 식생활 습관과 관련되어 있을 정도이므로 암예방에 있어서의 식품의 역할이 매우 크다 할 수 있다. 따라서 건전한 생활습관과 더불어 적절한 식품의 섭취는 암예방을 위한 기본이 될 것이다.

  • PDF