P-glycoprotein (P-gp) is the most studied ATP-binding cassette transporter, known to be able to cause multidrug resistance. The relevance of P-gp for clinical drug resistance remains controversial, however. Using our K14cre;Brca1F/F;p53F/F conditional mouse model of hereditary breast cancer, we previously found that modestly elevated expression levels of the mouse P-gp genes Mdr1a (Abcb1a) and/...

Primary resistance to vincristine (VCR) has been selected in rhabdomyosarcoma xenograft 11\Khl 2 by sequential administration of VCR at 1.5 and subsequently 3 mg/kg/passage. The resistant tumor (HxRhl2/ VCR-3) was approximately 4-fold resistant to VCR and resistance was stable in the absence of selecting pressure (>2 yr). HxRhl2/VCR-3 was 2to 3-fold cross-resistant to i.-phenyhlanine mustard (L...

Cetuximab, an antibody against the EGFR, has shown efficacy in treating head and neck squamous cell carcinoma (HNSCC), metastatic colorectal cancer, and non-small cell lung cancer (NSCLC). Despite the clinical success of cetuximab, many patients do not respond to cetuximab. Furthermore, virtually all patients who do initially respond become refractory, highlighting both intrinsic and acquired r...

Invasive mole belongs to gestational trophoblastic neoplasm, which is a highly curable group of pregnancy-related tumors. However, approximately 20% of gestational trophoblastic tumors will be resistant to or relapsed after initial chemotherapy. These resistant and relapsed lesions will require salvage chemotherapy with or without surgery. It is still unclear which regimens are the most effecti...

The results of chemotherapy of pancreatic cancer have been disappointing thusfar. Pancreatic tumors are primary resistant to available drugs. Why that is, is as hard to define as why normal tissues are resistant. Meaningful studies on drug resistance of pancreatic tumors can only be expected after a highly effective drug has been found. While waiting for this magic bullet to arrive, I shall rev...

Everolimus, an inhibitor of the mammalian target of rapamycin (mTOR), is effective in treating tumors harboring alterations in the mTOR pathway. Mechanisms of resistance to everolimus remain undefined. Resistance developed in a patient with metastatic anaplastic thyroid carcinoma after an extraordinary 18-month response. Whole-exome sequencing of pretreatment and drug-resistant tumors revealed ...

The guanosine triphosphate (GTP)-sensitive adenylate cyclase was studied In the crude membranes of three adrenocorticotrophlc hormone (ACTH)-resistant tumors and one prostaglandln E, (PGEi)-reslstant human adrenocortical tumor. In the ACTH-reslstant tumors, the steroidogenesis of Isolated adrenocortical cells was not stimu lated by ACTH,_24but was enhanced by PGE,; whereas in the PGErlnsensltiv...

Abstract Lung cancer is the most common to metastasize brain, with 50% of all brain metastases originating from lung primary tumors. Traditional therapy for includes surgical resection, radiation, and chemotherapy. Due presence blood-tumor barrier, penetration therapeutics significantly hindered. Even when used in combination, tumor recurrence regrowth after initial chemoradiotherapy remain a s...