Phase II study of S-1, an oral fluoropyrimidine, in patients with advanced or recurrent cervical cancer.

BACKGROUND: S-1 is an oral fluoropyrimidine. This phase II study was designed to evaluate the efficacy and safety of S-1 in patients with advanced or recurrent uterine cervical cancer. PATIENTS AND METHODS: S-1 35 mg/m(2) was given twice daily for 28 days repeated every 6 weeks. Eligible patients were women aged 20-74 years, who had Eastern Cooperative Oncology Group performance status of zero or one, who had stage IVB or recurrent uterine cervical cancer, and who had received no more than one platinum-containing chemotherapy regimen for stage IVB or recurrent disease. The primary end point was overall response rate (ORR) determined by RECIST. RESULTS: A total of 37 patients were enrolled in the trial and 36 were eligible. The median number of cycles administered was 4. The confirmed ORR was 30.6% (95% confidence interval 15.5% to 45.6%). The response rate for patients who had received platinum-based treatment including chemoradiotherapy was 31.8% (7 of 22). After a median follow-up duration of 25 months, the median time to progression and the median survival time were 5.2 and 15.4 months, respectively. The most frequent grade 3 or 4 adverse events were anemia (16%), anorexia (16%), and diarrhea (22%). CONCLUSIONS: This phase II study of S-1 in cervical cancer suggests a promising response rate and a contribution toward prolonging survival, with modest toxic effects. Phase III studies of S-1 in patients with advanced or recurrent cervical cancer are thus warranted.

The incidence, treatment and prognosis of cervical carcinoma in young women: a retrospective analysis of 4,975 cases in Japan.

OBJECTIVE: To determine the clinical characteristics of patients (young women) with cervical carcinoma aged less than 35 years. METHODS: Data from patients who were treated for cervical carcinomas from 1990 to 2000 in the Kinki District were retrospectively investigated for clinical stage, histologic type, treatment procedure and prognosis. RESULTS: Of a total of 4,975 cases, 441 patients were aged less than 35 years old. The incidence of cervical carcinoma in these women was 7.9% from 1990 to 1995, 9.1% from 1996 to 2000, and 9.5% from 2001 to 2005. FIGO Stage I included 374 cases, followed by, 49 in Stage II, 11 in Stage III, and seven in Stage IV. Squamous cell carcinoma incidence was 80.7% and non-squamous cell carcinoma incidence was 19.3%. Several types of surgery were performed in patients with Stage I and II, while patients with Stage III and IV were treated with radiotherapy and/or chemotherapy without any type of surgery. In patients who underwent lymphadenectomy, 21.1% cases had nodal involvement. The 5-year survival rate was 95% for Stage I disease, 73% for Stage II, 68% for Stage III, and 19% for Stage IV. CONCLUSION: The incidence of cervical carcinoma in young women slightly increased from 1990 to 2005. The prognosis of cervical carcinoma tends to be better in young women than in older patients, especially in Stage III disease.

Clinical outcome and prognostic factors in borderline tumors of the ovary. Results from 17 years' experience in the Kinki District of Japan (1990-2006).

PURPOSE OF INVESTIGATION: The clinical characteristics and long-term prognostic factors of borderline ovarian tumors (BOTs) were evaluated. METHODS: Data from patients who were treated for BOTs in the Kinki District of Japan from 1990 to 2006 were revieved. Two hundred and twenty-two cases were retrospectively investigated for stage, surgical procedure, histopathological features, adjuvant chemotherapy and prognosis. RESULTS: FIGO stages included 212 patients with Stage I disease, three with Stage II and seven with Stage III. One hundred and sixty-nine cases were diagnosed as mucinous tumor, 47 were serous, and six were others. Radical surgery was performed in 136 patients and conservative surgery in 86 patients. Only two patients showed invasive peritoneal implants. Forty patients received adjuvant chemotherapy. The survival rate was 95% at ten-years. Statistical analysis showed that earlier stage, absence of residual tumors, peritoneal implants, ovarian stromal involvement, and negative peritoneal cytology were associated with significantly better overall survival. CONCLUSION: The prognosis of patients with BOT is excellent. There are insufficient data to support a role for aggressive surgery and adjuvant chemotherapy for the possibility of prolonged survival.

Phase II study of irinotecan plus doxorubicin for early recurrent or platinum-refractory ovarian cancer: interim analysis.

The aim of this study was to evaluate the efficacy and toxicity of irinotecan and doxorubicin in the treatment of patients with early recurrent or platinum-refractory ovarian cancer. Nineteen woman from five different institutions were treated. Two patients had platinum-refractory cancer, 11 had platinum-resistant disease, and 6 had platinum-sensitive tumors. An intravenous infusion of Irinotecan (50 mg/m(2)) was given on days 1, 8, and 15, while doxorubicin (40 mg/m(2)) was administered as an intravenous bolus on day 3. This treatment schedule was repeated every 4 weeks. Among the 13 patients defined as having platinum-refractory/platinum-resistant disease, 4 patients achieved a clinical response (30.8%, 95% CI: 9.1-61.4), while only one of 6 patients defined as having platinum-sensitive disease achieved a clinical response (16.7%, 95% CI: 0.4-64.1). Leukopenia and neutropenia were the major dose-limiting toxicities. Grade 3 or 4 leukopenia and neutropenia were noted in 24 (48%) and 33 (66%) of the courses, while febrile neutropenia occurred in 2 courses. Five patients (26%) had grade 2 or worse diarrhea during 7 courses. Our data demonstrated that this regimen might be comparable to standard approved agents in patients with early recurrent or platinum refractory ovarian cancer.

Clinical outcomes of uterine sarcomas: results from 14 years worth of experience in the Kinki district in Japan (1990-2003).

To review clinical outcomes and therapeutic varieties, we were invited to submit data from the patients who were treated for uterine sarcomas in Japan from 1990 to 2003. Uterine sarcomas were defined as leiomyosarcoma (LMS), endometrial stromal sarcoma (ESS), and carcinosarcoma (CS). Of a total of 97 patients, 36 (37.1%) were diagnosed with LMS of the uterine corpus, 15 (15.5%) with ESS, 46 (47.4%) with CS. Median age at diagnosis was 59 (21-85) years. Clinical stages based on FIGO were 41 (42.3%) with stage I disease, 6 (6.2%) with staged II, 34 (35.1%) with stage III, and 16 (16.5%) with stage IV. The median follow-up period for all patients was 13 (1-108) months and median disease-free period was 9 (0-96) months. The 1-year survival rate and disease-free survival (DFS) rate were calculated in patients with all sarcomas (overall survival [OAS], 61.3%; DFS, 46.6%). Statistical analysis showed that younger age (less than 50 years), early stage (stages I and II), and surgical procedure (extended hysterectomy [EH] and radical hysterectomy [RH]) were associated with significantly better OAS. Histologic types did not affect the survival period. In conclusion, aggressive surgery including EH or RH at the time of initial operation offers the possibility of prolonged survival.

Preoperative chemotherapy with irinotecan and mitomycin for FIGO stage IIIb cervical squamous cell carcinoma: a pilot study.

PURPOSE OF INVESTIGATION: Patients with FIGO Stage IIIb cervical cancer show cancer propagation to pelvic side walls from the uterus, and the tumors cannot be completely removed by radical hysterectomy. Here, we examined the effects of preoperative irinotecan HCl (CPT-11)-combined chemotherapy on patients with unresectable Stage IIIb cervical squamous cell carcinoma. METHODS: Eleven patients agreed to participate in the pilot study and received preoperative chemotherapy. RESULTS: Cervical tumors of all 11 patients showed partial responses in tumor reduction, and radical hysterectomy was successfully performed in ten patients treated with CPT-11 and mitomycin C (MMC). One patient treated with CPT-11 and cisplatin had a 68% reduction of the primary cervical lesion but could not undergo radical surgery because of retroperitoneal cancer progression during chemotherapy. CONCLUSION: These results indicate that chemotherapy with CPT-11 and MMC could be a useful preoperative treatment for unresectable Stage IIIb cervical squamous carcinoma.

Apoptosis and the expression of Bax and Bcl-2 in hyperplasia and adenocarcinoma of the uterine endometrium.

BACKGROUND: Apoptosis plays a crucial role in carcinogenesis in various tumours. This study was designed to investigate the occurrence of apoptosis and the expression of Bcl-2 and Bax proteins in endometrial tumours of corpus uteri. METHODS: Endometrial tissues were obtained from 20 patients with endometrioid adenocarcinoma, 16 patients with endometrial hyperplasia, and 4 patients with myoma uteri (which were used as controls). The occurrence of apoptosis was examined by using molecular biochemical techniques. The expression of Bcl-2 and Bax proteins was also investigated using immunohistochemical staining with appropriate antibodies. RESULTS: The labelling of DNA in situ indicated that apoptotic cells were sporadically seen in postmenopausal endometrium (5.2 +/- 2.1, n = 4) and endometrial hyperplasia without atypia (2.6 +/- 0.5, n = 9). In contrast, labelled cells were detected in atypical endometrial hyperplasia (15.9 +/- 2.2, n = 7), and their numbers increased intensely in adenocarcinoma (29.3 +/- 3.7, n = 20). Autoradiographic analysis revealed DNA laddering in many cases of carcinoma. Bcl-2 was highly immunopositive in hyperplasia without atypia (36.2 +/- 6.5%, n = 9), but was decreased in the atypical endometrial hyperplasia (16.3 +/- 4.8%, n = 7). Large fractions of the carcinoma (6.3 +/- 1.8%, n = 20) and normal endometrium (2.8 +/- 1.4%, n = 4) were immunonegative or slightly immunopositive to Bcl-2. In contrast, Bax immunoreactivity was more frequent and stronger in adenocarcinoma (43.6 +/- 4.1%, n = 20) than that in normal endometrium (17.6 +/- 6.7%, n = 4) and hyperplasia (7.2 +/- 2.2%, n = 16). CONCLUSIONS: These results suggest that cells in hyperplasia expressing Bcl-2 might have prolonged survival ability. Neoplastic cells in adenocarcinoma might show apoptosis in association with a decreased expression of Bcl-2 and an increased expression of Bax. Therefore, the frequency of apoptosis and the expression of Bcl-2 and Bax might be correlated with carcinogenesis in the uterine endometrium of humans.

Apoptosis and the expression of Bcl-2 and Bax in patients with endometrioid, clear cell, and serous carcinomas of the uterine endometrium.

OBJECTIVES: Clear cell and serous carcinoma of the uterus are rare types of endometrial carcinomas. This study was designed to investigate the differential occurrence of apoptosis, Bcl-2, and Bax in endometrioid, clear cell, and serous carcinomas. METHODS: In a total of 28 endometrial carcinomas as well as 4 samples of normal postmenopausal endometria, apoptotic changes were examined using molecular biochemical techniques. The expression of Bcl-2 and Bax proteins was also investigated by immunohistochemical staining with appropriate antibodies. RESULTS: Labeling of DNA in situ indicated that apoptotic cells were sporadically seen in postmenopausal endometrium (5.2 +/- 2.1, n = 4). In contrast, cells undergoing apoptosis apparently were detected in endometrioid carcinoma (29.3 +/- 3.7, n = 20), and their numbers increased intensely in clear cell (49.5 +/- 5.6, n = 5) and serous carcinomas (50.8 +/- 6.0, n = 3). Autoradiographic analysis revealed that high-molecular-weight DNA was predominant in postmenopausal endometrium. However, a DNA ladder was identified in 7 of 10 carcinomas. Although Bcl-2 was immunonegative or faintly immunopositive in all cases, many cases of endometrioid carcinoma (43.6 +/- 4.1%, n = 20) were immunopositive for Bax, unlike postmenopausal endometrium (17.6 +/- 6.7%, n = 4). Moreover, the number of cells expressing Bax increased in clear cell (60.4 +/- 6.5%, n = 5) and serous carcinomas (66.8 +/- 7.6%, n = 3) compared with that in endometrioid carcinoma. CONCLUSIONS: These results indicate that apoptosis occurs in a specific population of cells in different histologic components of endometrial carcinomas. The expression of Bax, but not of Bcl-2, might suggest histologic differentiation in endometrial carcinomas.

Transient increases of apoptosis and Bax expression occurring during radiotherapy in patients with invasive cervical carcinoma.

BACKGROUND: Apoptosis plays a crucial role in radiation therapy (RT) in various carcinomas. This study was designed to investigate the relation between apoptosis and RT in invasive squamous cell carcinoma (ISCC) of the uterine cervix METHODS: Thirty-five specimens were obtained from 7 patients with ISCC before and during a fractionated RT. The occurrence of apoptosis was examined by end labeling of DNA gel fractionation and in situ 3' end labeling of DNA. The expression of Bax and Bcl-2 proteins was investigated by immunohistochemical staining. RESULTS: Autoradiographic analysis revealed that high molecular weight DNA was predominant in the untreated ISCC specimens. However, a ladder-like pattern, characteristic of the apoptotic breakdown of DNA, was identified at doses of 900 cGy and 1980 cGy. At doses >1980 cGy, DNA laddering disappeared without any extensive smearing. Quantitative analysis of low molecular weight fragments of DNA revealed significant increases at doses of 900 cGy and 1980 cGy compared with those before RT and at doses of >1980 cGy. Labeling of DNA in situ indicated that cells undergoing apoptosis increased dramatically at a dose of 900 cGy. However, apoptotic cells decreased at a dose of 3960 cGy. In addition, a large fraction of tumor cells was immunonegative for Bcl-2 before and during RT. By contrast, immunoreactive Bax was observed intensely in many neoplastic cells at doses of 900 cGy and 1980 cGy. CONCLUSIONS: The current investigation indicates that low doses of RT result in apoptotic cell death in ISCC in association with the increased expression of Bax but not with increased Bcl-2 expression.

Apoptosis and the expression of Bax and Bcl-2 in squamous cell carcinoma and adenocarcinoma of the uterine cervix.

BACKGROUND: Apoptosis plays a crucial role in the suicide and turnover of cells in various tumors. This study was designed to investigate the relation between apoptosis and the histologic types of cell in invasive cervical carcinoma. METHODS: Cervical tissues were obtained from 19 patients with invasive squamous cell carcinoma (ISCC), 9 patients with invasive endocervical adenocarcinoma (IEAC), and 15 patients with myoma uteri (which were used as controls). Each tissue was rapidly frozen and/or fixed in Bouin's solution. The occurrence of apoptosis was examined by end labeling of DNA with (alpha-32P)dideoxyATP and electrophoretic fractionation and by end labeling of DNA in situ with digoxigenin-dideoxyUTP. The expression of Bcl-2 and Bax proteins was examined by immunohistochemical staining with appropriate antibodies. RESULTS: Autoradiographic analysis revealed that high molecular weight DNA was predominant in the normal cervical epithelium (NCE) and in ISCC. However, a ladder-like pattern of DNA fragments, characteristic of the apoptotic breakdown of DNA, was identified in IEAC. Quantitative analysis of low molecular weight fragments of DNA revealed a significant increase in IEAC but not in ISCC compared with NCE. Labeling of DNA in situ indicated that cells undergoing apoptosis were predominant among the neoplastic cells of IEAC. However, no apoptotic cells were noted in ISCC, with the exception of cells in some tumor nests. A large fraction of IEAC and ISCC was immunonegative for Bcl-2. Although the expression of Bax was detected weakly in a small fraction of ISCC, strong expression of Bax was observed in all cases of IEAC. CONCLUSIONS: Apoptosis appears to occur in the cancerous cells of invasive adenocarcinoma of the uterine cervix in association with a high level of expression of Bax but not of bcl-2.

Immunohistochemical localization of activin A in human endometrial tissues during the menstrual cycle and in early pregnancy.

OBJECTIVE: To investigate the possible localization of activin A in human endometrial tissue. METHODS: Human endometrial tissue was collected from 33 patients who were undergoing abdominal hysterectomy. Human decidual tissue was collected from 11 patients, who were having a therapeutic abortion. Tissue was fixed in Bouin's solution and made into paraffin sections. Tissue sections were stained with monoclonal antibodies against the inhibin/activin alpha- and betaA-subunits and activin A using an avidin-biotin-peroxidase complex technique. RESULTS: No immunostaining with antibody against the alpha-subunit was observed in the human endometrium during the menstrual cycle or in the decidua during early pregnancy. By contrast, immunostaining for the betaA-subunit and activin A was observed in the cytoplasm of endometrial glands at all phases of the menstrual cycle and in the decidua during early pregnancy. The intensity of immunostaining for the betaA-subunit was strong during the menstrual phase, became weaker during the early proliferative phase, and was intense again at the late proliferative phase. The immunostaining for the betaA-subunit was weak during the early secretory phase and became very intense toward the midsecretory and late secretory phases. The intensity of immunostaining for activin A changed during the menstrual cycle and showed a tendency similar to that for betaA-subunit. The stromal cells were weakly immunoreactive with antibodies against the betaA-subunit and activin A from the menstrual to the midsecretory phase and became strong in the late secretory phase. Intense staining for the betaA-subunit and activin A was observed in the cytoplasm of decidual cells during early pregnancy. CONCLUSION: Activin A, but not inhibins, is localized in the endometrial tissue. The endometrium may be a major source of activin A during the normal menstrual cycle, and the decidua may be one of the sources of activin A during early pregnancy.

Apoptosis in human chorionic villi and decidua during normal embryonic development and spontaneous abortion in the first trimester.

To investigate possible apoptotic changes, the cleavage of DNA in human chorionic villi and decidua was examined during the first trimester of pregnancy by molecular biochemical techniques. Very limited but detectable cleavage of DNA was recognized in the chorionic villi and decidua in normal pregnancy. The characteristic apoptotic breakdown of DNA was recognized in the chorionic villi and decidua in cases of spontaneous abortion. Quantitative analysis of low molecular weight fragments of DNA revealed a significant increase in cases of spontaneous abortion compared to those in normal pregnancy. However, the extent of apoptosis was not correlated with either urinary levels of human chorionic gonadotropin (hCG) and/or gestational age. An analysis in situ revealed cells undergoing apoptosis in the cytotrophoblast in normal pregnancy, and apoptotic cells were predominant in the syncytiotrophoblast in cases of spontaneous abortion. It is shown that apoptosis occurs in the human conceptus during the first trimester of normal pregnancy and is greatly intensified in cases of spontaneous abortion. In addition, the results indicate that apoptosis might play a critical role in embryonic development and wastage in humans.

Quick responses of plasma amino acid concentration to changes in dietary amino acid levels in rats.

In order to evaluate the availability of plasma amino acid (AA) concentration as a parameter to determine AA requirements of rats within a short period, the response of the plasma AA concentration to changes in dietary AA levels was studied. In Experiment 1, to clarify whether the plasma AA concentration responded to changes in dietary AA levels and how long the response of the plasma AA concentration was maintained, 10 male rats were fed a casein diet for a 7 day period, and then the food was changed to AA diets. The serine (Ser), glycine (Gly) and threonine (Thr) levels were decreased from 120, 90 to 60% of the casein diet at 7-day intervals successively. Blood samples were taken at 2, 4 and 7 days after changing the diet, from the vena caudalis by vein puncture. In all cases, the plasma AA concentration responded to changes in dietary AA within 2 days, and the response was maintained until the 7th day. Experiment 2 was conducted to confirm that the plasma concentration of each AA responded to the changes in dietary AA levels at the first day and the responses of the plasma concentration of AA were maintained until the 4th day after changing the dietary AA levels, when the combination of metabolically unrelated AA was added. Five rats in A groups were fed diets with added arginine + Thr, histidine + methionine, lysine or isoleucine + Ser, and five rats in B groups were fed diets with added Gly + valine, leucine + phenylalanine or Thr + tyrosine + valine for a 4-day period successively. Blood samples were taken at 1 and 4 days after changing diets. Although the plasma concentrations of histidine, leucine, methionine, phenylalanine and Ser did not respond to changes in dietary AA levels, those of other AA responded at 1 day and the responses were maintained until the 4th day.

Apoptosis in human chorionic villi and decidua in normal and ectopic pregnancy.

To investigate possible effects of implantation on apoptosis, we examined the cleavage of DNA in human chorionic villi and decidua in intrauterine and ectopic pregnancy. Very limited but detectable cleavage of DNA was recognized in the chorionic villi and decidua in normal pregnancy. A ladder pattern, characteristic of the apoptotic breakdown of DNA, was present in the villi in tubal pregnancy. High molecular weight DNA was predominant in the decidua in tubal pregnancy. Quantitative analysis of low molecular weight fragments of DNA revealed a significant increase in the villous tissue, together with a significant decrease in the decidual tissue, in tubal pregnancy as compared to those in normal pregnancy. An analysis in situ revealed that apoptotic cells were predominant in the syncytiotrophoblast in tubal pregnancy. In decidual tissue, labelled cells were occasionally seen in normal pregnancy, and their numbers decreased in tubal pregnancy. The present study demonstrates that apoptosis occurs in the villi, but not in the decidua in tubal pregnancy, unlike the situation in normal pregnancy. Our results suggest that the implantation site might affect the occurrence of apoptotic changes in early pregnancy of humans.

Apoptosis of human ovary and uterine endometrium during the menstrual cycle.

To investigate apoptotic changes in the ovary or uterine endometrium, we studied the cleavage of DNA in these tissues obtained from regularly cycling women by in situ analysis of DNA integrity and quantitative end labeling of DNA gel fractionation. In situ analysis of several sized atretic follicles of ovaries revealed that granulosa cells showed positive staining to some extent, however, these methods do not discriminate between cells undergoing apoptosis and those undergoing necrosis. Total DNA extracted from human corpora lutea (CL) of the early luteal phase contained predominantly high molecular weight DNA, whereas CL of the midluteal phase exhibited the appearance of DNA cleavage into low molecular weight ladders characteristic of apoptosis. Although apoptotic DNA cleavage of human CL increased from the midluteal phase to the late luteal phase, CL of early pregnancy did not exhibit apoptotic DNA fragmentation. Both large and small luteal cells were the primary cell type exhibiting DNA cleavage in human CL of the midluteal and late luteal phases and in regressive CL. Biochemical analysis of human endometrium revealed that the ladder pattern cleavage of DNA was identified at three different phases of the menstrual cycle, namely the early proliferative, late secretory, and menstrual phases. Cells undergoing apoptosis were scattered in the functional layer of the early proliferative endometrium, but not in the late proliferative phase to midsecretory phase: At the beginning of the late secretory phase, apoptosis reappeared in the stromal cells and spread gradually to almost all components of the functional layer. By contrast, cells in the basal layer showed no evidence of apoptosis throughout the menstrual cycle. The present findings suggest that: (1) human luteal regression may be mediated by apoptosis; (2) CL of early pregnancy may be rescued from luteolysis through inhibition of the occurrence of apoptotic luteal cell death, and (3) apoptosis occurs in specific populations of endometrial cells during the human endometrial cycle. In conclusion, apoptosis might play an important role in the regulation of the menstrual cycle in women.

Apoptosis in the human uterine endometrium during the menstrual cycle.

To investigate apoptotic changes, we studied the cleavage of DNA in the uterine endometrium obtained from regularly cycling women by a quantitative end labeling of DNA gel fractionation and in situ analysis. The ladder pattern characteristic of the apoptotic cleavage of DNA into fragments of low mol wt was identified at three different phases of the cycle, namely the early proliferative, late secretory, and menstrual phases. However, DNA of high mol wt was predominant in the endometrium during the late proliferative, early secretory, and midsecretory phases. Our analysis in situ revealed that cells undergoing apoptosis were scattered in the functional layer of the early proliferative endometrium. However, apoptotic cells were no longer detectable during the late proliferative phase, and none was observed until the midsecretory phase. At the beginning of the late secretory phase, apoptosis reappeared in the stromal cells and spread gradually to almost all components of the functional layer. By contrast, cells in the basal layer showed no evidence of apoptosis throughout the menstrual cycle. The present study demonstrates that apoptosis occurs in specific populations of cells during three phases of the human endometrial cycle. Our results indicate, moreover, that apoptosis might have an important role in the regulation of the menstrual cycle in women.

Apoptosis of human corpora lutea during cyclic luteal regression and early pregnancy.

To elucidate the role of apoptotic cell death in human corpus luteum (CL) regression, human CL during the menstrual cycle and early pregnancy were isolated and processed for biochemical (radio-labeling) analysis of DNA integrity. Total DNA extracted from human CL of the early luteal phase contained predominantly high mol wt DNA, whereas CL of the midluteal phase exhibited the appearance of DNA cleavage into low mol wt ladders characteristic of apoptosis. Although apoptotic DNA cleavage of human CL significantly increased from the midluteal phase to the late luteal phase (P < 0.05), CL of early pregnancy did not exhibit apoptotic DNA fragmentation by biochemical analysis. In situ analysis of DNA fragmentation revealed that both large and small luteal cells exhibited DNA cleavage in human CL of the midluteal and late luteal phases and in regressive CL. The present findings suggest that 1) human luteal regression may be mediated by apoptosis; and 2) CL of early pregnancy may be rescued from luteolysis through inhibiting the occurrence of apoptotic luteal cell death.