PURPOSE To compare the expression of multidrug-resistant proteins in retinoblastoma tumors among eyes treated with primary enucleation. METHODS A group of 18 patients with unilateral retinoblastoma with advanced intraocular disease was selected for the study. All patients had undergone primary enucleation. A histologic specimen from each patient was retrieved from the pathology archives and a...

Tumor cells often become resistant to DNA damage-based therapy; however, the underlying mechanisms are not yet understood. Here, we show that tumor cells exposed to DNA damage counteract cell death by releasing the antiapoptotic protein, survivin, from mitochondria. This is independent of p53, and requires activated checkpoint kinase 2 (Chk2), a putative tumor suppressor. Molecular or genetic t...

In a cooperative study specimens of 37 patients with stage III and IV ovarian carcinomas who had been treated with chemotherapy were investigated utilizing flow cytometry and an in vitro short-term test for predicting resistance. Patients with aneuploid tumors had significantly shorter survival rates than did those with diploid tumors. Patients whose tumors showed a low G0/G1 cell proportion or...

Glioblastoma (GBM) is a cancer comprised of morphologically, genetically, and phenotypically diverse cells. However, an understanding of the functional significance of intratumoral heterogeneity is lacking. We devised a method to isolate and functionally profile tumorigenic clones from patient glioblastoma samples. Individual clones demonstrated unique proliferation and differentiation abilitie...

Cancer is a main public health problem all over the world. It affects millions of humans no matter their age, gender, education, or social status. Although chemotherapy is the main strategy for the treatment of cancer, a major problem limiting its success is the intrinsic or acquired drug resistance. Therefore, cancer drug resistance is a major impediment in medical oncology resulting in a fail...

BACKGROUND Malignant ovarian germ cell tumors are rare, and often treatable with surgery and chemotherapy. Few data are available for treatment of platinum-resistant tumors. CASE A 31 year old gravida 0 with a 20 cm pelvic mass was found to have a malignant ovarian germ cell tumor after she underwent debulking surgery. She initially responded to chemotherapy; however her AFP began to rise bef...

Despite the remarkable clinical response of melanoma harboring BRAF mutations to BRAF inhibitors (BRAFi), most tumors become resistant. Here, we identified the downregulation of the ubiquitin ligase RNF125 in BRAFi-resistant melanomas and demonstrated its role in intrinsic and adaptive resistance to BRAFi in cultures as well as its association with resistance in tumor specimens. Sox10/MITF expr...

Osteosarcomas are rare tumors with aggressive biology. It is important to refer such patients a high-volume center, where an accurate diagnosis and optimal treatment more likely be performed. In contrast Ewing's sarcoma, conventional osteosarcomas believed generally resistant radiation therapy, the main modalities surgery chemotherapy. this clinical case, we demonstrate efficacy of combined ost...

About 50% of cancer patients receive radiation therapy. Here we investigated the hypothesis that tumor response to radiation is determined not only by tumor cell phenotype but also by microvascular sensitivity. MCA/129 fibrosarcomas and B16F1 melanomas grown in apoptosis-resistant acid sphingomyelinase (asmase)-deficient or Bax-deficient mice displayed markedly reduced baseline microvascular en...

Tumor drug resistance significantly limits the success of chemotherapy in the clinic. Tumor cells utilize multiple mechanisms to prevent the accumulation of anticancer drugs at their intracellular site of action. In this study, we investigated the anticancer efficacy of doxorubicin in combination with photodynamic therapy using methylene blue in a drug-resistant mouse tumor model. Surfactant-po...