KRAS mutation signature in colorectal tumors significantly overlaps with the cetuximab response signature.

A French prospective pilot study for identifying dihydropyrimidine dehydrogenase (DPD) deficiency in breast cancer patients (pts) receiving capecitabine (cap)

e13519 Background: For fluoropyrimidines, and especially cap, Health Authorities point out that DPD deficiency confers a significant risk of major toxicity (tox). Identification of at-risk pts is thus relevant. This multicentric prospective study of the French GPCO group (Groupe de Pharmacologie Clinique Oncologique, Unicancer) evaluated the sensitivity, specificity and predictive values of DPD phenotyping and genotyping for predicting severe cap-related tox in metastatic breast cancer pts. Methods: 303 pts were included (15 institutions), 88% received cap as monotherapy, 28% were treated as first line (mean dose at 1st cycle 1957 mg/m2/d). Pre-treatment dihydrouracil (UH2) and uracil (U) …

Patients with colorectal tumors with microsatellite instability and large deletions in HSP110 T17 have improved response to 5-fluorouracil–based chemotherapy.

Background & Aims Patients with colorectal tumors with microsatellite instability (MSI) have better prognoses than patients with tumors without MSI, but have a poor response to 5-fluorouracil–based chemotherapy. A dominant-negative form of heat shock protein (HSP)110 (HSP110DE9) expressed by cancer cells with MSI, via exon skipping caused by somatic deletions in the T 17 intron repeat, sensitizes the cells to 5-fluorouracil and oxaliplatin. We investigated whether HSP110 T 17 could be used to identify patients with colorectal cancer who would benefit from adjuvant chemotherapy with 5-fluorouracil and oxaliplatin. Methods We characterized the interaction between HSP110 and HSP110DE9 using su…

Colon cancer molecular subtype intratumoral heterogeneity and its prognostic impact: An extensive molecular analysis of the PETACC-8

Expression of a mutant HSP110 sensitizes colorectal cancer cells to chemotherapy and improves disease prognosis

Heat shock proteins (HSPs) are necessary for cancer cell survival. We identified a mutant of HSP110 (HSP110ΔE9) in colorectal cancer showing microsatellite instability (MSI CRC), generated from an aberrantly spliced mRNA and lacking the HSP110 substrate-binding domain. This mutant was expressed at variable levels in almost all MSI CRC cell lines and primary tumors tested. HSP110ΔE9 impaired both the normal cellular localization of HSP110 and its interaction with other HSPs, thus abrogating the chaperone activity and antiapoptotic function of HSP110 in a dominant-negative manner. HSP110ΔE9 overexpression caused the sensitization of cells to anticancer agents such as oxaliplatin and 5-fluorou…