Enhanced production of reactive oxygen species in HeLa cells under concurrent low­dose carboplatin and Photofrin® photodynamic therapy.

Concurrent low­dose carboplatin/Photofrin® photodynamic therapy (ccPDT) has been shown to promote relapse­free complete tumor regression in cervical or endometrial cancer patients as a fertility­preservation therapy. This study aimed to investigate the molecular mechanism of the enhanced therapeutic efficacy of ccPDT by determining intracellular reactive oxygen species (ROS) and necrotic or apoptotic cell damage in HeLa cells loaded with fluorescent oxidant agents and Photofrin or/and carboplatin under light irradiation. The cytotoxic effects of ccPDT were compared when monitored with a light dose under carboplatin or Photofrin alone. Photofrin­PDT alone did not enhance either hydroxyl radicals (OH•) or superoxide anions (O2•-), but a slight enhancement of hydrogen peroxide (H2O2) production was observed. A larger enhancement of ROS production was obtained in a dose­dependent manner following ccPDT, especially OH• and H2O2, in conjunction with both necrotic and apoptotic cell death, compared with necrotic­prone PDT alone. The carboplatin­mediated Fenton reaction: 2[PtII]2 + H2O2 → [Pt2.25]4 + OH¯+ OH• was proposed to explain the dose­dependent enhancement of OH•. In conclusion, the therapeutic enhancement of ccPDT in vitro was attributable to the carboplatin­mediated synergetic production of OH▪ and apoptotic cellular damage, compared with Photofrin­PDT alone.

Development and validation of novel digitalized cervicography system.

OBJECTIVE: Digital cervicography systems would be expected to reduce the costs of film cervicography, and provide the opportunity for "telemedicine-based" screening. We aimed to develop web-based digital cervicography system, and validate it compared with conventional film cervicography. METHODS: A hundred cases from five centers were prospectively included, and cervical images (analogue, digitalized by scanning analogue, and digital) were taken separately using both analogue (Cerviscope) and digital camera (Dr. Cervicam) in each patient. Nine specialists evaluated the three kinds of images of each case with time interval between evaluations of each image. To validate novel digitalized system, we analyzed intra-observer variance among evaluation results of three kinds of images. RESULTS: Sixty-three cases were finally analyzed after excluding technically defective cases that cannot be evaluable on analogue images. The generalized kappa for analogue versus digital image was 0.83, for analogue versus scanned image 0.72, and for digital versus scanned image was 0.71; all were in excellent consensus. CONCLUSION: Digitalized cervicography system can be substituted for the film cervicography very reliably, and can be used as a promising telemedicine tool for cervical cancer screening.

Protective effects of green tea polyphenol against cisplatin-induced nephrotoxicity in rats.

OBJECTIVE: This study is to compare the effects of green tea polyphenol (GTP) pre-treatment with those of GTP post-treatment on cisplatin (CP)-induced nephrotoxicity in rat. METHODS: Male Sprague-Dawley rats were randomly divided into six groups. Animals in the control group received 0.9% saline (intraperitoneal); animals in the GTP group received 0.9% saline and GTP (0.2% GTP as their sole source of drinking water); the CP group received only CP (7 mg/kg, intraperitoneal); the CP+preGTP group received GTP from two days before CP to four days after CP and the CP+postGTP group received GTP for four days after CP. CP-induced renal toxicity was evaluated by plasma creatinine and blood urea nitrogen (BUN) concentrations; kidney tissue γ-glutamyl transpeptidase (GGT) and alkaline phosphatase (AP) activities and histopathological examinations. RESULTS: High serume creatinine and BUN concentrations were observed in CP treated rats. The GGT and AP activites were lower in kidney of CP treated rats compared to control rats. In addition, treatment with CP resulted in development of a marked tubular necrosis, and tubular dilation in kidney of rats. Pretreatment with GTP resulted in markedly reduced elevation of serum creatinine and BUN amounts and changes of GGT and AP activity in kidney induced by CP. CP-induced histopathological changes, including tubular necrosis and dilation, were ameliorated in GTP pre-treated rats, compared to CP alone or GTP post-treated rats. CONCLUSION: These results demonstrate that GTP might have some protective effect against CP-induced nephrotoxicity in rat, and GTP pre-treatment was more effective than GTP post-treatment on reduction of CP-induced renal dysfunction.

Breast diseases during pregnancy and lactation.

Breast is a typical female sexual physiologic organ that is influenced by steroid hormone from menarche until menopause. Therefore various diseases can be developed by continuous action of estrogen and progesterone. Breast diseases are mainly categorized as benign and malignant. It is very important to distinguish the malignancy from breast diseases. However, it is very difficult to diagnose malignancy in pregnant and lactating women even though the same breast diseases took place. Therefore, we will review breast diseases such as breast carcinoma during pregnancy and lactation.

Comparison of single-, double- and triple-combined testing, including Pap test, HPV DNA test and cervicography, as screening methods for the detection of uterine cervical cancer.

Cervical cancer is a serious disease that threatens the health of women worldwide. This study compared the sensitivities and false-positive rates of cervical cytology (Pap smear), human papilloma virus (HPV) DNA test, cervicography, first double-combined testing (cervical cytology and HPV DNA test), second double-combined testing (cervical cytology and cervicography) and triple-combined testing (cervical cytology, HPV DNA test and cervicography). The study included 261 patients screened for uterine cervical cancer. All women simultaneously underwent cervical cytology, HPV DNA test and cervicography for uterine cervical cancer screening and colposcopically directed biopsy for diagnostic evaluation. The triple-combined testing was consistently the most sensitive among the cervical screening tests. The second double-combined testing, with a sensitivity rate of 98.1% was more sensitive than the first double-combined test (92.3%). However, cervical cytology was most specific (93.5%) and showed the highest positive predictive value (77.8%). The sensitivity of cervical cytology was markedly improved in combination with HPV DNA test and cervicography. Thus, the triple-combined testing, which improves the high false negativity of cervical cytology, may be an effective tool in uterine cervical cancer screening, pending confirmation of the effectiveness in a mass screening study.

Photodynamic therapy for breast cancer in a BALB/c mouse model.

OBJECTIVE: Photodynamic therapy (PDT) has been used for superficial neoplasms and its usage has been recently extended to deeper lesions. The purpose of this study was to observe whether or not PDT can cure breast cancer in the solid tumor model, and to define the critical point of laser amount for killing the cancer cells. METHODS: Twenty four BALB/c mouse models with subcutaneous EMT6 mammary carcinomas were prepared. Mice were divided into eight groups depending on the amount of illumination, and the tumor size was between 8 mm and 10 mm. We began by peritoneal infiltration with a photosensitizer 48 hours prior to applying the laser light, and then we applied a non-thermal laser light. The energy was from 350 J/cm(2) to 30 J/cm(2) to the cancer. RESULTS: Regardless of the tumor size from 8 mm to 10 mm, all mice apparently showed positive results via PDT. We also did not find any recurrence over 90 J/cm(2). In all models, the color of the breast cancer lesions began to vary to dark on 2 days post PDT and the tumor regression began simultaneously. Also, we confirmed the complete regression of the breast cancer 21 days after PDT. CONCLUSION: We confirmed that PDT may treat breast cancers that are sized less 10 mm in mouse models. The moderate energy to destruct the breast cancer cells may be 90 J/cm(2). Therefore, we can expcect that PDT may be utilized to treat breast cancer, but we need more experience, skills and processing for clinical trials.

Successful full term pregnancy and delivery after concurrent chemo-photodynamic therapy (CCPDT) for the uterine cervical cancer staged 1B1 and 1B2: Preserving fertility in young women.

► Photodynamic therapy can treat lesions with highly reactive single oxygen. ► CCPDT (Concurrent Chemo Photodynamic Therapy) is defined as PDT with chemotherapy. ► CCPDT can treat larger and deeper lesions than PDT due to PCI concept. ► Complete remission would be possible in uterine cervical cancer by CCPDT. ► Uterine cervix and corpus can be preserved in CCPDT.

A case of neutrophilia related to a cytokine-producing relapsed squamous cell carcinoma of the uterine cervix arising from the rectovaginal septum.

Paraneoplastic neutrophilia caused by a squamous cell carcinoma of the uterine cervix has been seen rarely. We report a case of relapsed squamous cell carcinoma of the uterine cervix with severe neutrophilia, rapid tumor growth and aggressive clinical course, possibly due to autocrine stimulation of cell growth by G-CSF and IL-6 without other possible causes of neutrophilia.

TRAIL-induced cell death and caspase-8 activation are inhibited by cisplatin but not carboplatin.

OBJECTIVE: Platinum (Pt) based drugs including cisplatin and carboplatin are widely used as anticancer drugs in various human cancers. Many studies have shown that chemotherapeutic agents synergistically enhance cell death induced by death ligands. However it has been recently reported that cisplatin may inhibit tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cell death through inactivation of caspases. Thus, we investigated whether carboplatin also inhibits TRAIL-induced cell death. METHODS: HeLa cells were treated with TRAIL in the presence of cisplatin or carboplatin, and cell death was analyzed using the crystal violet staining method. Caspase activation was checked through detection of Bid cleavage by Western blotting using anti-Bid antibody. RESULTS: Cisplatin inhibits TRAIL-induced cell death in HeLa cells; however, carboplatin enhanced TRAIL-induced cell death. Whereas cisplatin inhibited caspase-8-mediated Bid cleavage, carboplatin had no effect on caspase-8 activity. CONCLUSION: Although cisplatin and carboplatin are platinum-containing cancer therapeutic agents, they have the opposite effects on TRAIL-induced cell death.

Struma ovarii and peritoneal strumosis with thyrotoxicosis.

BACKGROUND: Struma ovarii is a highly specialized form of mature ovarian teratoma consisting of thyroid tissue and exhibiting all the histological features of the thyroid gland. Malignant transformation of thyroid tissue in struma ovarii and metastasis are extremely uncommon. In rare cases, benign thyroid tissue may spread to the peritoneal cavity, and pathologic examination of the peritoneal implants shows multiple nodules of varying sizes of mature thyroid tissue similar to struma ovarii. This condition is termed "peritoneal strumosis." SUMMARY: We report a 49-year-old woman with struma ovarii complicated by peritoneal strumosis with thyrotoxicosis. After surgical resection of the struma ovarii and peritoneal strumosis the patient became euthyroid. CONCLUSION: To the best of our knowledge this is the first report of a patient with peritoneal strumosis complicated by thyrotoxicosis. The relative contribution to circulating thyroid hormones by the patient's struma ovarii as compared to the peritoneal strumosis is not known.

The efficacy of sonographic morphology indexing and serum CA-125 for preoperative differentiation of malignant from benign ovarian tumors in patients after operation with ovarian tumors.

OBJECTIVE: To evaluate the value of sonographic morphology indexing (MI) system and serum CA-125 levels in the assessment of the malignancy risk in patients with ovarian tumors. METHODS: From September 2000 to July 2006, 202 patients who underwent surgery for ovarian tumors were reviewed retrospectively. In all patients, the MI score and serum CA-125 level were measured preoperatively. The association of the final pathologic diagnosis with the MI score and serum CA-125 level were examined. RESULTS: There were 26 malignant tumors out of 141 ovarian tumors with a MI >/=5 (18%). With a cut-off value of 5, the sensitivity, specificity, PPV, and NPV of MI scores were 0.743, 0.293, 0.181, and 0.845, respectively. There were 22 malignant tumors out of 54 ovarian tumors with serum CA-125 >30 u/ml (41%). With a cut-off value of 30 u/ml, the sensitivity, specificity, PPV, and NPV of serum CA-125 level were 0.667, 0.808, 0.407, and NPV 0.925, respectively. On ROC curve, the optimal cut-off value of MI score was 6.5-7.5 and that of serum CA-125 level was 25.6-28.5 u/ml. With a cut-off value of 7, the sensitivity and 1-specificity of MI score were 0.875-0.917 and 0.023-0.203, respectively. After the exclusion of teratoma cases, the sensitivity and 1-specificity of MI score were 0.875-0.917 and 0.046-0.138, respectively. With a cut-off value of 25.6-28.5 u/ml, the sensitivity and 1-specificity of serum CA-125 level were 0.958 and 0.203-0.215, respectively. CONCLUSION: The sonographic MI system is an accurate and simple method to differentiate a malignant tumor from a benign ovarian tumor. The accuracy of the sonographic MI system improved when the serum CA-125 level was considered and ovarian teratomas were excluded.

Photodynamic therapy-generated tumor cell lysates with CpG-oligodeoxynucleotide enhance immunotherapy efficacy in human papillomavirus 16 (E6/E7) immortalized tumor cells.

Immunotherapy with photodynamic therapy (PDT) offers great promise as a new alternative for cancer treatment; however, its use remains experimental. In this study, we examined the immunotherapeutic significance of human papillomavirus (HPV)-immortalized tumor cell lysates induced by PDT with CpG-oligodeoxynucleotide (ODN). PDT-cell lysates were generated by irradiating Radachlorin (5 microg/mL) preloaded TC-1 cells carrying HPV 16 E7. PDT-cell lysates plus ODN coinjection for protection against E7-expressing tumors as well as specific immune responses were evaluated with the following tests: heat shock protein 70 (HSP70) enzyme-linked immunosorbent assay, in vitro and in vivo tumor growth inhibition, interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) assay, cytotoxic T-lymphocyte assay, and fluorescence activated cell sorting (FACS) analysis. PDT-cell lysates plus ODN coinjection showed a significant suppression of tumor growth at both prophylactic and therapeutic levels, compared to PDT (or F/T)-cell lysates or ODN alone. In addition, we evaluated the level of the immune response with the coinjection. HSP70, an important regulator of inflammatory and immune response, was observed in abundance in the PDT-cell lysates. IFN-gamma production and cytotoxic T lymphocytes (CTL) responses were induced by PDT-cell lysates plus ODN injection. The coinjection resulted in PDT-cell lysate-specific antibodies (IgG1, IgG2a, IgG2b, and IgG3) and T-helper cell responses significantly higher than PDT-cell lysates alone. Moreover, IFN-gamma production and CTL responses were significantly induced in the PDT-cell lysate plus ODN immunized groups. These enhanced immune responses appeared to be mediated by CD8+ T cells only. These data suggest that PDT-cell lysates plus ODN injection may be an effective approach to induce CTL immune responses as a possible immunotherapeutic strategy for cancer therapy.

Adenovirus-mediated p53 treatment enhances photodynamic antitumor response.

Photodynamic therapy (PDT) has been reported to be effective for treating various tumors and to induce apoptosis in many tumor cells. In this study, we evaluated the ability of PDT combined with a tumor suppressor factor, recombinant adenovirus p53 (AdCMVp53), to induce apoptosis as well as cell growth inhibition in CaSki human cervical cancer cells and in nude mice with implanted CaSki cells. To examine levels of apoptosis, CaSki cells were treated with PDT and/or AdCMVp53, and an annexin V-staining assay was then conducted. In addition, Western blot analysis was done to identify p53 induction at the cellular and tumor tissue levels. PDT+AdCMVp53 cotreatment caused remarkable inhibition of CaSki cell proliferation, as compared with the individual treatments. In parallel with the inhibition of cell proliferation, the cotreatment caused a significantly greater increase in the annexin V-stained cell population compared with the individual treatments, as determined by fluorescence-activated cell-sorting analysis. The Western blotting assay also showed significantly more cellular p53 expressed after PDT+AdCMVp53 cotreatment than after each separate treatment. This was consistent with observations of tumor tissue in the mouse system. However, apoptosis- related protein, p21, was significantly suppressed by PDT+AdCMVp53 cotreatment, contrary to treatment with AdCMVp53 alone. Taken together, these findings suggest that PDT plus AdCMVp53 gene therapy exerts more potent antitumor effects on human cervical cancer cells, with induction of apoptosis at least through activation in p53 protein at the cellular and tumor tissue levels.

Searching for pathogenic gene functions to cervical cancer.

OBJECTIVES: Molecular pathology of cervical cancers associated with human papillomavirus (HPV) infection is presently unclear. In an effort to clarify this issue, we investigated gene expression profiles and pathogenic cellular processes of cervical cancer lesions. METHODS: Tissues of 11 patients (invasive cancer stages Ib-IIIa) were investigated by a cDNA microarray of 4700 genes, hierarchical clustering and the Gene Ontology (GO). RESULTS: We identified 74 genes showing a more than 2-fold difference in their expression in at least 8 out of 11 patients. Among these, 33 genes were up-regulated, in contrast, 41 genes were down-regulated. The gene expression profiles were classified into mutually dependent 345 function sets, resulting in 611 cellular processes according to the GO. The GO analysis showed that cervical carcinogenesis underwent complete down-regulation of cell death, protein biosynthesis, and nucleic acid metabolism. Also, genes belonging to nucleic acid binding and structural molecule activity were significantly down-regulated. In contrast, significant up-regulation was shown in skeletal development, immune response, and extracellular activity. CONCLUSIONS: These data suggest that the regulated genes and cellular processes could be further used for predicting prognosis and diagnosis of cervical cancer patients, and further investigation and functional characterization of the identified genes is warranted.

Activity of green tea polyphenol epigallocatechin-3-gallate against ovarian carcinoma cell lines.

PURPOSE: A constituent of green tea, (-)-epigallocatechin-3-gallate (EGCG), is known to possess anti-cancer properties. In this study, the time-course of the anticancer effects of EGCG on human ovarian cancer cells were investigated to provide insights into the molecular-level understanding of the growth suppression mechanism involved in EGCG-mediated apoptosis and cell cycle arrest. MATERIALS AND METHODS: Three human ovarian cancer cell lines (p53 negative, SKOV-3 cells; mutant type p53, OVCAR-3 cells; and wild type p53, PA-1 cells) were used. The effect of EGCG treatment was studied via a cell count assay, cell cycle analysis, FACS, Western blot and macroarray assay. RESULTS: EGCG exerts a significant role in suppressing ovarian cancer cell growth, showed dose dependent growth inhibitory effects in each cell line and induced apoptosis and cell cycle arrest. The cell cycle was arrested at the G1 phase by EGCG in SKOV-3 and OVCAR-3 cells. In contrast, the cell cycle was arrested in the G1/S phase in PA-1 cells. EGCG differentially regulated the expression of genes and proteins (Bax, p21, Retinoblastoma, cyclin D1, CDK4 and Bcl-X(L)) more than 2 fold, showing a possible gene regulatory role for EGCG. The continual expression in p21WAF1 suggests that EGCG acts in the same way with p53 proteins to facilitate apoptosis after EGCG treatment. Bax, PCNA and Bcl-X are also important in EGCG-mediated apoptosis. In contrast, CDK4 and Rb are not important in ovarian cancer cell growth inhibition. CONCLUSION: EGCG can inhibit ovarian cancer cell growth through the induction of apoptosis and cell cycle arrest, as well as in the regulation of cell cycle related proteins. Therefore, EGCG-mediated apoptosis could be applied to an advanced strategy in the development of a potential drug against ovarian cancer.

Photodynamic effects of Radachlorin on cervical cancer cells.

PURPOSE: Photodynamic therapy (PDT) is a novel treatment modality, which produces local tissue necrosis with laser light following the prior administration of a photosensitizing agent. Radachlorin has recently been shown to be a promising PDT sensitizer. In order to elucidate the antitumor effects of PDT using Radachlorin on cervical cancer, growth inhibition studies on a HPV-associated tumor cell line, TC-1 cells in vitro and animals with an established TC-1 tumor in vivo were determined. MATERIALS AND METHODS: TC-1 tumor cells were exposed to various concentrations of Radachlorin and PDT, with irradiation of 12.5 or 25 J/cm(2) at an irradiance of 20 mW/cm(2) using a Won-PDT D662 laser at 662 nm in vitro. C57BL/6 mice with TC-1 tumor were injected with Radachlorin via different routes and treated with PDT in vivo. A growth suppression study was then used to evaluate the effects at various time points after PDT. RESULTS: The results showed that irradiation of TC-1 tumor cells in the presence of Radachlorin induced significant cell growth inhibition. Animals with established TC-1 tumors exhibited significantly smaller tumor sizes over time when treated with Radachlorin and irradiation. CONCLUSION: PDT after the application of Radachlorin appears to be effective against TC-1 tumors both in vitro and in vivo.

In vivo activity of the potent oxytocin antagonist on uterine activity in the rat.

Oxytocin antagonist (OTA), TT-235, was developed by our group and shown to inhibit either spontaneous or oxytocin-induced uterine contractions in primates. The purpose of the present study was to confirm the duration of TT-235 to block oxytocin-induced uterine contractions in estrous rats. In Experiment 1, the time-response of the three OTAs on uterine contractility was examined. The rats were anesthetized and cannulas were placed in the jugular vein for infusing vehicle (sterile saline), Antag I, Antag II and TT-235. The uterine activity was monitored through a water-filled balloon-tipped cannula placed in the uterine horn. The uterine contractile activity was determined as the integrated area for 10 minutes. Each OTA was administered as a single bolus injection of 5 microg, followed by 100 mU of oxytocin 5 minutes later, also done as a single bolus. Oxytocin injection of the same dosage was repeated every hour for 5 hours. Experiment 2 determined the effect of the three OTAs on uterine oxytocin receptor number (Rn) and binding affinity (Kd). Rats treated with either OTA or vehicle were sacrificed at 0.5 and 4 hours for receptor assay. In Experiment 1, Antag I, Antag II and TT-235 inhibited the integrated uterine response to oxytocin at 5 minutes by 76%, 77% and 80%, respectively, compared to controls (p<0.05). Two hours after injecting Antag I, inhibition of uterine contractility was 55% lower than controls (p<0.05). At 3 hours, uterine contractility was no longer affected in rats treated with Antag I compared with controls. The suppressive uterine activity with Antag II continued up to 3 hours. However, uterine contractility remained lower (53%) in rats treated with TT-235 5 hours later. In Experiment 2, TT-235 induced a significant decrease (p<0.05) in oxytocin receptor number and binding affinity at both 0.5 and 4 hours compared with controls. Antag I and Antag II did not alter oxytocin receptor number or binding affinity significantly at each time point studied compared with controls. In conclusion, TT-235 may inhibit the uterine response to oxytocin by decreasing oxytocin receptor numbers and oxytocin binding affinity, which might explain the prolonged oxytocin antagonist activity of TT-235.

cDNA Microarray Analysis of Gene Expression Profiles Associated with Cervical Cancer.

PURPOSE: The molecular pathology of cervical cancers associated with human papillomavirus infection is presently unclear. In an effort to clarify this issue, the gene expression profiles and pathogenic cellular processes of cervical cancer lesions were investigated. MATERIALS AND METHODS: Cervical cancer biopsies were obtained from patients at the Department of Obstetrics and Gynecology, The Catholic University of Korea. The disease status was assigned according to the International Federation of Gynecology and Obstetrics. The tissue samples of 11 patients (invasive cancer stage Ib- IIIa) were investigated by a cDNA microarray of 4, 700 genes, hierarchical clustering and the Gene Ontology (GO). Total RNA from cervical cancer and non-lesional tissues were labeled with Cy5 and Cy3. The HaCaT human epithelial keratinocyte cell line was used as a negative control cell. The stages of invasive cancer were Ib to IIIb. All specimens were obtained by punch-biopsies and frozen in liquid nitrogen until required. RESULTS: 74 genes, showing more than a 2 fold difference in their expressions, were identified in at least 8 of the 11 patients. Of these genes, 33 were up-regulated and 41 were down-regulated. The gene expression profiles were classified into 345 mutually dependent function sets, resulting in 611 cellular processes according to their GO. The GO analysis showed that cervical carcinogenesis underwent complete down-regulation of cell death, protein biosynthesis and nucleic acid metabolism. The genes related to nucleic acid binding and structural molecule activity were also significantly down-regulated. In contrast, significant up-regulation was shown in the skeletal development, immune response and extracellular activity. CONCLUSION: These data are suggestive of potentially significant pathogenetic cellular processes, and showed that the down-regulated functional profiling has an important impact on the discovery of pathogenic pathways in cervical carcinogenesis. GO analysis can also overcome the complexity of the expression profiles of the cDNA microarray via a cellular process level approach. Thereby, a valuable prognostic candidate gene, with real relevance to disease-specific pathogenesis, can be found at the cellular process levels.

Photogem Induces Necrosis in Various Uterine Cervical Cancer Cell Lines by PDT.

PURPOSE: In order to elucidate the antitumor effect of photodynamic therapy (PDT), using a derivative of the photosensitizing agent hematoporphyrin (Photogem) and a diode laser, the cell death of uterine cancer cell lines (CaSki, HT3, HeLa, and SKOV-3), and mice transplanted with TC-1 lung cancer cells, were evaluated. MATERIALS AND METHODS: The morphological changes, MTT assay, flow cytometry, cytotoxicity and tumor growth inhibition study were evaluated at various time intervals after the PDT. RESULTS: The results showed that the survival rates of each cell line decreased with time and dose response after performing the PDT. Also, the PDT-induced damage of cancer cells was almost entirely confined to necrosis of the tumor cells in the early time courses. The irradiation of CaSki cells in the presence of Photogem induced plasma membrane disruption and cell shrinkage, indicating the plasma membrane as the main target for Photogem. In the in vivo experiment, significantly longer survival and a significantly smaller tumor size were seen over the time courses of the Photogem with irradiation compared to the untreated control groups; resorption of the tumor was also observed after the PDT treatment. CONCLUSION: Collectively, our results indicated that Photogem possesses anti-tumor effects, and necrosis-like death, with plasma membrane damage, was postulated to be the principal mechanism of the antitumor effect of the PDT using Photogem.