Impact of COVID-19 on the performance of a radiation oncology department at a major comprehensive cancer centre in Poland during the first ten weeks of the epidemic.

The outbreak of SARS-CoV-2 coronavirus rapidly altered radiotherapy service delivery around the world. AIM: The main objective of this study was to assess the impact of precautionary measures implemented in response to the COVID-19 pandemic on the performance of a radiation oncology departments and on mitigation the risk of COVID-19 contagion between and among patients and staff. METHODS: The study period was from March 15 until May 22, 2020. We evaluated total number of patients irradiated and those who initiated treatments, taking into account tumours localisations. We assessed the relationship of potential risk of contagion with patients' domiciles locations in regions with high number of COVID19 case. RESULTS AND CONCLUSIONS: The number of patients treated with radiotherapy during the study period decreased due to precautionary measures. After five weeks, the number of radiotherapy treatments began to increase. Just over half of the radiotherapy patients (53.5%) treated at the GPCC reside in the city of Poznan or in one of the ten surrounding counties where COVID19 incidence was low and reached at the end of the study period cumulative number of cases n = 204. The precautionary measures were effective qRT-PCR tests were performed in 1545 individuals (patients and hospital staff) revealing four staff members and none patient with a positive PCR result. Immunoglobulin testing was performed in 1132 individuals (patients and hospital staff). A total of 63 individuals were positive for antibodies.

Images in two prostate cancer patients of second primary cancers: Hodgkin's lymphoma and lung adenocarcinoma.

Hodgkin's lymphoma and lung adenocarcinoma as second primary cancers in prostate cancer (PC) patients although are rare should be considered as important for the future of the PC patients.

KIT mutations and CD117 overexpression are markers of better progression-free survival in vulvar melanomas.

BACKGROUND: Few studies have addressed prognostic markers and none has correlated molecular status and prognosis in vulvar melanomas. OBJECTIVES: To evaluate the clinicopathological features of 95 cases of vulvar melanoma. METHODS: p53, CD117, Ki-67, neurofibromin, brafv600e and nrasq61r immunostains, and molecular analyses by either targeted next-generation or direct sequencing, were performed on available archival materials. RESULTS: Molecular testing detected mutations in KIT (44%), BRAF (25%), NF1 (22%), TP53 (17%), NRAS (9%) and TERT promoter (9%). Co-mutation of KIT and NF1 and of KIT and NRAS were identified in two and one cases, respectively. KIT mutations were significantly associated with better progression-free survival in univariate analyses. In multivariate analyses CD117 expression was significantly associated with better progression-free survival. Tumour thickness was significantly associated with worse progression-free and overall survival, and perineural invasion significantly correlated with reduced melanoma-specific survival and reduced overall survival. Cases were from multiple centres and only a subset of samples was available for molecular testing. CONCLUSIONS: KIT mutations and CD117 overexpression are markers of better progression-free survival. In addition to its prognostic value, molecular testing may identify cases that might respond to targeted agents or immunotherapeutic approaches.

Two unusual cases: vulvar lipoma - description of the largest case in literature. Developing myoma with the longest pedicle.

The authors present two cases of benign tumors one located on the outer surface of the vulva, and the second extending beyond the vagina. The first, originating from the right pudendal lip, a lipoma measuring 23 cm in greatest diameter, weighing 6.6 kg, and the second a pedunculated, uterine smooth muscle myoma with a pedicle of 6.5 cm, maximum diameter 18 cm, weight 700 grams, which caused significant metroptosis. Operative procedures in each case were free of complications.

A case of a 20-kg fibrothecoma.

A case report of a 50-cm diameter and 20-kg mass of benign ovarian tumor. Total abdominal hysterectomy with a bilateral salpingooophorectomy was performed with full patient recovery. Fibrothecomas can remain long asymptomatic and can grow to giant sizes.

The effect of tobacco smoke on oxytocin concentrations and selected oxidative stress parameters in plasma during pregnancy and post-partum - an experimental model.

BACKGROUND: Tobacco smoking is a serious threat to life and health of society. Among the most vulnerable to the toxic effects of tobacco smoke are foetuses and newborns. The objective of the research was to assess the impact of tobacco smoke exposure on oxytocin levels and biochemical oxidative stress parameters during pregnancy and after birth in an experimental model. METHODS: In the experiment, exposure to tobacco smoke of gravid and non-gravid rats was monitored. A reliable biomarker of exposure - cotinine - was used in the process and it was determined by means of high-performance liquid chromatography with diode array detection, which ensured high analytical accuracy and precision. Determination of oxytocin was performed by means of enzyme-linked immunosorbent assay. The levels of selected oxidative stress parameters: total protein concentration, uric acid, trolox equivalent antioxidant capacity, protein S-nitrosylation and lipid peroxidation (thiobarbituric acid reactive substances) were measured by spectrophotometric methods. RESULTS AND CONCLUSIONS: The effect of prenatal and postnatal exposure to tobacco smoke was a lower medium body mass of rat foetuses and pups. Oxidative stress during pregnancy, additionally intensified by tobacco smoke exposure, led to adaptive changes in properties of plasmatic antioxidant barriers. Moreover, the disturbance of oxidoreductive balance by tobacco smoke affects oxytocin fluctuations, what was observed in this study during lactation period. Therefore, women who smoke may breastfeed their children less frequently and for a shorter period.

[Risk of perinatal complication and egg donation: Role of resorting to cross-border care?] / Les risques périnataux sont-ils plus importants après don d'ovocytes à l'étranger ?

OBJECTIVES: In France, egg donation is covered by Social insurance among women<43 years old. Because of shortage of egg donor, women aged 43 years or more cannot resort to egg donation in French infertility centers, leading them to turn to the foreign centers having practices different and less regulated than in France. We are thus brought to take care of the pregnancy and of the delivery of these women. Our objective was to estimate if the perinatal risks are more important after egg donation abroad than in case of egg donation in a French center. MATERIAL AND METHODS: Retrospective study between January, 2010 and April, 2013, comparing women having had an egg donation to Cochin then having delivered in the maternity hospital of their choice (n=88) and the women having had an egg donation abroad then having delivered in the Port-Royal maternity (n=121). First, the modalities of egg donation were compared between the Cochin hospital and the foreign centers. Second, the obstetric and perinatal outcomes were compared between both groups, then by stratifying according to the type of pregnancy (singleton or multiple). RESULTS: Among women having had an egg donation abroad, the age of the donor was lower (25.7 vs. 31.7, P=0.001), the average number of embryos transferred higher (2.1±0.6 vs. 1.7±0.5, P=0.001) and the rate of multiple pregnancies higher (47.9% vs. 9.1%, P=0.001) than among women having had an egg donation at Cochin. We observed after egg donation abroad compared to egg donation at Cochin, a birth weight significantly lower (2678±745g vs. 3045±682g, P=0.001) and a prevalence of intrauterine growth retardation higher (11.1% vs. 4.2%, P=0.04). Among singletons, abnormal placentation was more frequent in case of egg donation abroad (17.5% vs. 5.1%, P=0.02). In case of twin pregnancy, we highlighted very high rates of complications, without significant difference according to the place where egg donation was practiced. CONCLUSION: We observed an increased risk of intrauterine growth retardation after egg donation abroad, which could essentially be explained by the association between advanced maternal age and multiple gestation. For other obstetric and perinatal complications, the differences between both groups were less important than expected, but very high in both groups, whether the egg donation was realized in France or abroad. The complications seem mainly due to the multiple gestations, justifying the transfer of a single embryo whenever possible.

Recurrent CDK1 overexpression in laryngeal squamous cell carcinoma.

In this study, we analyzed the expression profile of four genes (CCNA2, CCNB1, CCNB2, and CDK1) in laryngeal squamous cell carcinoma (LSCC) cell lines and tumor samples. With the application of microarray platform, we have shown the overexpression of these genes in all analyzed LSCC samples in comparison to non-cancer controls from head and neck region. We have selected CDK1 for further analysis, due to its leading role in cell cycle regulation. It is a member of the Ser/Thr protein kinase family of proven oncogenic properties. The results obtained for CDK1 were further confirmed with the application of reverse transcription quantitative polymerase chain reaction (RT-qPCR) technique, Western blot, and immunohistochemistry (IHC). The observed upregulation of CDK1 in laryngeal squamous cell carcinoma has encouraged us to analyze for genetic mechanisms that can be responsible this phenomenon. Therefore, with the application of array-CGH, sequencing analysis and two methods for epigenetic regulation analysis (DNA methylation and miRNA expression), we tried to identify such potential mechanisms. Our attempts to identify the molecular mechanisms responsible for observed changes failed as we did not observe significant alterations neither in the DNA sequence nor in the gene copy number that could underline CDK1 upregulation. Similarly, the pyrosequencing and miRNA expression analyses did not reveal any differences in methylation level and miRNA expression, respectively; thus, these mechanisms probably do not contribute to elevation of CDK1 expression in LSCC. However, our results suggest that alteration of CDK1 expression on both mRNA and protein level probably appears on the very early step of carcinogenesis.

New application of carbon nanotubes in haemostatic dressing filled with anticancer substance.

The drug-carrier system used as innovative haemostatic dressing with oncostatic action is studied. It is obtained from CDDP (cisplatin) doped SWCNT (single walled carbon nanotubes), modified and purified by H2O2 in hydrothermal treatment process. In the in vivo nephron sparing surgery (NSS) study we used 35 BALB/c nude mice with induced renal cancer using adenocarcinoma 786-o cells. Animals were divided into four groups: CDDP(M-), CDDP(M+), CONTROL(M-) and CONTROL(M+). In CDDP(M-) and CDDP(M+) groups we used, intraoperatively, carbon nanotubes filled with cisplatin (CDDP). In CONTROL(M-) and CONTROL(M+) groups carbon nanotubes were used alone. During NSS free margin (M-) or positive margin (M+) was performed. In the CDDP(M-) group, we do not observe local tumor recurrences. In Group CDDP(M+) only one animal was diagnosed with tumor recurrence. In control groups the recurrent tumor formation was observed. In our study, it is shown that CDDP filled SWCNT inhibit cancer recurrence in animal model NSS study, and can be successfully applied as haemostatic dressings for local chemoprevention.

How to isolate urothelial cells? Comparison of four different methods and literature review.

The aim of this study is to present the comparison of four different methods for urothelial cell isolation and culture and compare them to methods cited in the literature. Four different techniques were examined for urothelium isolation from rat bladders. Isolation effectiveness was calculated using trypan blue assay. Confirmation of isolated cell phenotype and comparison with native bladder tissue was confirmed using immunohistochemical (IHC), immunocytochemical (ICC) and immunofluorescence (IF) analysis. The method with bladder inversion and collagenase P digestion resulted in the highest number of isolated cells. These cells showed positive expression of cytokeratin 7, 8, 18, α6-integrin and p63. Our results and the literature review showed that the best method for urothelium bladder isolation is dissection of the epithelium layer from other bladder parts and digestion of mechanically prepared tissue in a collagenase solution.

Acroangiodermatitis in a leg amputee using a suction-socket prosthesis: clinical, histological as well as HHV-8 and CD34 immunohistochemical study.

Acroangiodermatitis (AAD) is a rare, vascular phenomenon of unclear pathogenesis. Itchy, lichenoid, purple/violaceous/yellowish/brownish papules/nodules, plaques/patches mainly on lower limbs occasionally evolve into verrucous lesions and recurrent painful ulcerations. Elevated vein and capillary pressure due to the sub-atmospheric suspension system seems to be the triggering factor for angioproliferation in the amputation stump. A middle-aged male amputee, a suction-socket prosthesis user, showing combined clinical, histological and immunohistochemical (HHV-8 negative; CD34 and CD31 expressed in endothelial, but not perivascular, cells) features of AAD is presented. Dermatologists, orthopedic surgeons, pathomorphologists, but also prosthesis makers and amputees themselves, should be aware of AAD as suction-socket prostheses become increasingly popular.

Bovine neonatal pancytopenia in calves in Poland.

Bovine neonatal pancytopenia (BNP), a newly emerged syndrome of discussed etiology in calves, has been diagnosed since 2006. Here we describe first cases of BNP in Poland. Between September 2008 and April 2011, 62 cases of BNP were diagnosed in dairy calves. Bleeding skin lesions were mostly pronounced in summer and early autumn. Severe thrombocytopenia was observed in all sick animals. All calves came from herds vaccinated against BVDV infection with PregSure BVD vaccine (Pfizer). Substitution of colostrum from dams of BNP positive calves with colostrum from dams from herds free of BNP was the only effective measure to avoid new cases in affected herds.

Labeling of microvessel density, lymphatic vessel density and potential role of proangiogenic and lymphangiogenic factors as a predictive/prognostic factors after radiotherapy in patients with cervical cancer.

INTRODUCTION: Angiogenesis, formation of a new blood vessel from the existing vascular network, is essential for tumor growth, progression and metastasis. Vascular endothelial growth factor (VEGF) has been identified to be one of the most important factors of angiogenesis. VEGF-C, a novel member of the family, is a relatively specific lymphangiogenic growth factor. It is tempting to suggest that cervical cancer is one of the most common malignancies in a woman's life. Its prognostic factors are tumor stage, lymph node status, histologic type, level of hemoglobin. However, little is known about prognostic or/and predictive significance of angiogenesis in cervical cancer. OBJECTIVE: This prospective study is an attempt to evaluate serum VEGF-A, VEGF-C, microvessel density (MVD), and lymphatic vessel density (LMVD) in cervical cancer and the correlations with clinicopathologic features. MATERIAL AND METHODS: Blood samples were collected from 58 patients affected by FIGO I-IV stage cervical cancer, who were admitted to the Department of Oncology and Brachytherapy Collegium Medicum in Bydgoszcz of Nicolaus Copernicus University. Serum VEGF-A/VEGF-C concentrate was determined by means of a quantitative sandwich enzyme immunoassay (ELISA). All tumor samples were taken from cross section during the first brachytherapy. Then they were examined by immunohistochemical studies with podoplanin antibody and anti-CD31 antibody. The present analysis was used to evaluate MVD and LMVD. RESULTS: The median serum VEGF-A was 734.76 pg/ml (range from 86.39 pg/ml - 2200.00 pg/ml), and VEGF-A was only correlated with after treatment hemoglobin concentration (p = 0.046, R = -0.3450). The median serum VEGF-C was 145.72 pg/ml (range 131.08 - 233.60 pg/ml). Serum VEGF-C levels measured in patients were associated with primary tumor size. We observed significantly higher serum VEGF-C in localized disease (FIGO I, II) in comparison to advanced tumors (232.44 pg/ml vs 152.45 pg/ml; p = 0.034). The median LMVD was 6.25 (range 3.5-10.0) and median blood vessel density was 12.5 (range 9.5-23.0). We found significantly higher lymphatic vessel density in patients with Gl/G2 grade of differentiation than in those with G3 (9.93 vs 6.25; p = 0.0398). We observed a statistically significant correlation between MVD and LMVD; (p = 0.032). CONCLUSION: In conclusion, our study suggests that serum VEGF-A, VEGF-C, LMVD and MVD play an important role in tumor growth and progression in cervical cancer. Nonetheless, further studies are essential to explore the underlying mechanism.

Morphological and urodynamic evaluation of urinary bladder wall regeneration: muscles guarantee contraction but not proper function--a rat model research study.

BACKGROUND: Numerous studies are ungoing to develop a substitute for the native urinary bladder wall. The principals of tissue engineering approaches to urinary bladder wall augmentation require a favorable environment for smooth muscle regeneration, which is crucial for bladder function. This study was performed to evaluate bone marrow mesenchymal stem cells (BMSC) seeded on to amniotic membranes fixed to Tachosil sponges as grafts for urinary bladder muscle layer augmentation in a syngenic rat model. MATERIALS AND METHODS: Amniotic membranes seeded with BMSC and covered by Tachosil sponges were implanted as multilayer grafts into nine rats to regenerate the urinary bladder wall. The control group consisted of 12 healthy rats. Urodynamic examinations included contraction, elasticity, compliance, and urinary bladder motor activity. Hematocylin and eosin and Masson's trichrome stains were used to evaluate muscle regeneration; histological data were digitally analyzed with the ImageJ tool. RESULTS: The area of muscle bundles ranged from 5% to 25% or 32% to 41% in control versus reconstructed bladders, respectively. Among nine animals with reconstructed urinary bladders, urodynamic evaluation revealed bladder motor hyperactivity with regular (n = 4) or irregular (n = 1) storage and voiding phases, as well as proper bladder motor activity with a large bladder capacity (n = 1). No bladder contractility was recorded in one case and large stones developed in two animals, which made functional studies impossible. CONCLUSIONS: Regenerated smooth muscle cells created an autonomic cell population that was poorly assimilated to the rest of the urinary bladder wall. The histological presence of a regenerated muscle layer did not guarantee proper urinary bladder function.

In vitro optimization of the Gallus domesticus oviduct epithelial cells culture.

The aim of this experiment was to establish an efficient method for isolation and further culture in vitro of the normal chicken oviduct epithelial cells (COEC) for cell-based research models. Different factors were tested to optimize COEC primary culture for repeatable results: the origin of isolated cells (oviduct Infundibulum or Magnum section); the oviduct tissue dissociation procedure (mechanical scrapping or mincing), tissue digestion times (15, 30 and 45 min), the culture plates coating (colagene I, polystyrene surface or 3T3 feeder layer), the growth media (classic DMEM/Ham's F12 and defined serum-free medium, Lonza Switzerland), incubation temperature (37 °C vs 41°C) and different cell seeding numbers: 0.2M, 0.5M and 1.0M cells/well. The COEC isolated by mincing the Infundibular neck and digestion of tissue for 30 min formed cell aggregates of bright colour and gave proliferating colonies of epithelial-like character which was the best result obtained from all applied procedures in our studies. The fibroblast-like cells considered as contaminants occurred only sporadically up to day 7 of culture. Seeding about 1M cells in 1 mL of serum-free medium onto 12-well dishes gave the optimal growth of colonies resulting in 5 to 7 confluent culture wells from a single oviduct sample. Feeder layer and collagen I did not improve adhesion of the COEC to the culture vessel. Adoption of 37 °C and 41 °C did not reveal apparent differences to the condition of cultured COEC. Cell differentiation and proliferation potential depends on number and replicative capacity of isolated progenitors. The progenitors are responsible for holoclones formation and good culture growth. The percentage of colonies developed from the cells isolated from Infundibulum was greater than that of other samples in our studies. We conclude that the model of COEC primary cultures from different segments of oviduct, in particular infundibulum, should be incorporated to the range of avian cells research as this work generates questions about undocumented sources of oviduct progenitor cells.

Association between oocyte donation and maternal and perinatal outcomes in women aged 43 years or older.

BACKGROUND: Although older maternal age is a risk factor for pregnancy complications, an increasing number of women delay conception until the age of 40, and some must resort to IVF with oocyte donation. Our objective was to study the association between IVF, both with and without oocyte donation, and maternal and perinatal outcomes in a population of older women. METHODS: This retrospective study covered all women, aged 43 or more, who gave birth between 2008 and 2010. Univariate and multivariate analyses with logistic regression models were used to compare maternal and perinatal outcomes as a function of mode of conception: without IVF, with IVF using own oocytes or with IVF and oocyte donation. RESULTS: The study included 380 women, including 40 who had IVF without oocyte donation (10.5%) and 104 who had both (27.4%). There were 326 singleton and 54 multiple pregnancies. Overall, the complication rate was high: 8.7% pre-eclampsia, 6.1% gestational diabetes, 20.2% preterm delivery and 8.2% very preterm delivery (before 33 weeks), 44.8% Cesarean sections and 7.4% severe post-partum hemorrhage (PPH). The pre-eclampsia rate differed significantly between the groups (3.8% after no IVF, 10.0% after IVF only and 19.2% after IVF with oocyte donation, P< 0.001). After adjustment, the risk of pre-eclampsia was significantly higher in women with donated oocytes compared with pregnant women without IVF [adjusted OR = 3.3 (1.2-8.9)]. The rate of twin pregnancy was significantly higher in women with IVF and oocyte donation (39.4 versus 15.0% with IVF only and 2.5% without IVF, P< 0.001). Twin pregnancy was significantly associated with the risk of preterm delivery [adjusted OR = 8.9 (4.0-19.9)] and PPH [adjusted OR = 3.5 (1.3-9.5)]. CONCLUSION: In women aged 43 years or older, pregnancies obtained by IVF with oocyte donation are associated with higher rates of pre-eclampsia and twin pregnancies than those obtained without IVF or with IVF using their own oocytes.

Cardiovascular findings in women suffering from Turner syndrome requesting oocyte donation.

BACKGROUND: Through oocyte donation (OD), women with Turner syndrome (TS) may achieve motherhood. However, this population has a high prevalence of cardiac malformations and carry a risk for aortic dissection that is increased by pregnancy. Until recently, the necessity for a specialized cardiac evaluation before pregnancy was underestimated as was the need for follow-up through adulthood. The aim of this study was to evaluate the follow-up (mainly cardiovascular) of women with TS requesting OD. METHODS: Disease monitoring since diagnosis and prior cardiac evaluations conducted out of our centre were assessed in 25 women with TS who requested OD. New cardiac evaluations using echocardiography and magnetic resonance imaging were performed by our specialized cardiologist in 18 of these patients. RESULTS: We observed that the medical follow-up of women with TS was often deficient throughout adulthood. Most of the prior cardiac evaluations performed by cardiologists not accustomed to women with TS, either before (n = 8) or when starting OD (n = 12), were considered normal. However, when revaluated by a cardiologist who is familiar with TS, seven women were diagnosed with a bicuspid aortic valve and thus excluded from OD. In addition, when appropriate screening was conducted by our referent cardiologist before OD no cardiac complication was observed during pregnancy or delivery. CONCLUSIONS: Careful follow-up, including cardiac evaluation, should be recommended for women diagnosed with TS, before and after puberty. Moreover, assessment of cardiovascular parameters by a cardiologist familiar with TS should be routinely repeated before undertaking OD.

Doxorubicin-induced F-actin reorganization in cofilin-1 (nonmuscle) down-regulated CHO AA8 cells.

The actin cytoskeleton plays an important role in many cellular processes, including cell mortality, mitosis, cytokinesis, intracellular transport, endocytosis and secretion but also is involved in gene transcription. The dynamics of the actin cytoskeleton is controlled by different classes of actin-binding proteins (ABPs) which regulate the polymerization of actin filaments. In this report we used siRNA against cofilin-1 (nonmuscle) to demonstrate the effect of cofilin on the nuclear and cytoplasmic actin pools in CHO AA8 cells after exposition to various concentrations of doxorubicin. The immunofluorescence studies showed doxorubicin dose dependent tendency to formation the multinucleated giant cells, but also the increase of fluorescence intensity of cofilin in nuclei of untransfected cells. Induction of cell death with doxorubicin treatment in untransfected cells revealed both mitotic catastrophe (in both lower and higher doxorubicin doses) and apoptosis (mostly in higher doxorubicin doses), whereas among cofilin-1 down-regulated cells we observed only mitotic catastrophe. The results suggest that cofilin has apoptosis-inducing ability and that mitotic catastrophe is independent from F-actin content in cell nucleus. In this point of view we conclude that different mechanisms of chromatin reorganization are involved in these two processes. Moreover, we suppose that apoptosis and mitotic catastrophe are independent from each other.

Morphological and mechanical changes in juxtarenal aortic segment and aneurysm before and after open surgical repair of abdominal aortic aneurysms.

OBJECTIVE: The aim of study was to assess how the ultrastructure of the wall of aortic aneurysms, sac and neck influences aortic wall distensibility and proximal dilatation 2 years after open repair. METHODS: Biopsies for electron microscopy were taken from aneurysmal sac and neck of 30 patients. Patients were assessed by computed tomography (CT) and ultrasound for aneurysm diameter and distensibility (M-mode ultrasonography). RESULTS: Postoperative CT of the aortic stump distinguished two groups. Group I (n = 11) with little enlargement, median 1 mm (1-3 mm) and group II (n = 19) with significant aortic enlargement, median 5.2 mm (4-12 mm). In group II, changes in elastic fibres in the aneurysm neck were comparable to, but as extreme as in the aneurysm sac. For group I, the distensibility of the aneurysmal sac was significantly lower than in the neck or at the renal arteries. For group II, the distensibility in both the neck and sac was significantly lower than at the juxtarenal segment (p = 0.01). The biopsies of group II patients showed the extensive degeneration of normal architecture, which was associated with altered wall distensibility in both the aneurysmal neck and sac. CONCLUSIONS: Disorganisation and destruction of normal aortic architecture at the ultrastructural level are associated with decreasing aortic distensibility. Low aortic neck distensibility is associated with proximal aortic dilatation at 2 years postoperatively.

Actin reorganization in CHO AA8 cells undergoing mitotic catastrophe and apoptosis induced by doxorubicin.

Doxorubicin (DOX) is a drug widely used in cancer chemotherapy. Although it has been proven that DOX kills tumor cells, the triggered modes of cell death are not fully understood. There is some evidence that, depending on the dose of DOX, the treated cells undergo senescence, mitotic catastrophe, apoptosis or necrosis. The aim of this study was to assess the type of CHO AA8 cell death induced with different DOX doses. In this context, we also assessed organization and distribution of F-actin, which integrity was suggested to be indispensable for apoptosis. Following treatment with 0.5 and 1 microM DOX, the giant multinucleated cells with extended network of fine microfilaments appeared. Notably, in the nuclei of the enlarged cells microscopy and cytometric analysis showed the presence of F-actin. DOX (2.5 microM) caused the appearance of the giant cells and with apoptotic features and signs of autophagy vacuolization. Flow cytometric studies indicated a dose-dependent increase in the number of TUNEL-positive cells and cells stained with both Annexin V and PI. Cell cycle analysis revealed the increase in the hyperploid DNA content. Our results suggest that treatment of CHO AA8 cells with different DOX doses caused mitotic catastrophe that was followed by apoptosis with signs of autophagy. The increase in F-actin content in the nuclei of the dying cells was evident. We hypothesize that in CHO AA8 cells F-actin may be involved in chromatin reorganization undergoing cell death.