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Background KRAS mutations in colorectal cancer primary tumors predict resistance to anti-Epidermal Growth Factor Receptor (EGFR) monoclonal antibody therapy in patients with metastatic colorectal cancer, and thus represent a true indicator of EGFR pathway activation status.Methodology/Principal Findings KRAS mutations were retrospectively studied using polymerase chain reactions and subsequent sequencing of codons 12 and 13 (exon 2) in 110 patients with metastatic colorectal tumors. These studies were performed using tissue samples from both the primary tumor and their related metastases (93 liver, 84%; 17 lung, 16%). All patients received adjuvant 5-Fluorouracil-based polychemotherapy after resection of metastases. None received anti-EGFR therapy. Mutations in KRAS were observed in 37 (34%) of primary tumors and in 40 (36%) of related metastases, yielding a 94% level of concordance (kappa index 0.86). Patients with primary tumors possessing KRAS mutations had a shorter disease-free survival period after metastasis resection (12.0 vs 18.0 months; P = 0.035) than those who did not. A higher percentage of KRAS mutations was detected in primary tumors of patiens with lung metastases than in patients with liver metastases (59% vs 32%; p = 0.054). To further evaluate this finding we analyzed 120 additional patients with unresectable metastatic colorectal cancer who previously had their primary tumors evaluated for KRAS mutational status for clinical purposes. Separately, the analysis of these 120 patients showed a tendency towards a higher degree of KRAS mutations in primary tumors of patients with lung metastases, although it did not reach statistical significance. Taken together the group of 230 patients showed that KRAS was mutated significantly more often in the primary tumors of patients with lung metastases (57% vs 35%; P = 0.006).Conclusions/SignificanceOur results suggest a role for KRAS mutations in the propensity of primary colorectal tumors to metastasize to the lung.

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The aim of this study was to investigate selected proteomic markers of the metabolic phenotype of breast carcinomas as prognostic markers of cancer progression. For this purpose, a series of 101 breast carcinomas and 13 uninvolved breast samples were examined for quantitative differences in protein expression of mitochondrial and glycolytic markers. The beta-subunit of the mitochondrial H(+)-ATP synthase (beta-F1-ATPase) and heat shock protein 60 (Hsp60), and the glycolytic glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase and lactate dehydrogenase were identified by immunological techniques. Correlations of the expression level of the protein markers and of the ratios derived from them were established with the clinicopathological information of the tumors and the follow-up data of the patients. The metabolic proteome of breast cancer specimens revealed a pronounced shift towards an enhanced glycolytic phenotype concurrent with a profound alteration on the mitochondrial beta-F1-ATPase/Hsp60 ratio when compared with normal samples. Discriminant analysis using markers of the metabolic signature as predictor variables revealed a classification sensitivity of approximately 97%. Kaplan-Meier survival analysis showed that several of the proteomic variables significantly correlated with overall and disease-free survival of the patients. The expression level of beta-F1-ATPase per se allowed the identification of a subgroup of breast cancer patients with significantly worse prognosis. Multivariate Cox regression analysis indicated that tumor expression of beta-F1-ATPase is a significant marker independent from clinical variables to assess the prognosis of the patients. We conclude that the alteration of the mitochondrial and glycolytic proteomes is a hallmark feature of breast cancer further providing relevant markers to aid in the prognosis of breast cancer patients.

Reactive Oxygen Species (ROS) result from cell metabolism as well as from extracellular processes. ROS exert some functions necessary for cell homeostasis maintenance. When produced in excess they play a role in the causation of cancer. ROS mediated lipid peroxides are of critical importance because they participate in chain reactions that amplify damage to biomolecules including DNA. DNA attack gives rise to mutations that may involve tumor suppressor genes or oncogenes, and this is an oncogenic mechanism. On the other hand, ROS production is a mechanism shared by many chemotherapeutic drugs due to their implication in apoptosis control. The ROS mediated cell responses depend on the duration and intensity of the cells exposing to the increased ROS environment. Thus the status redox is of great importance for oncogenetic process activation and it is also implicated in tumor susceptibility to specific chemotherapeutic drugs. Phospholipid Hydroperoxide Glutathione Peroxidase (PH-GPx) is an antioxidant enzyme that is able to directly reduce lipid peroxides even when they are bound to cellular membranes. This article will review the relevance of oxidative stress, particularly of lipid peroxidation, in cell response with special focus in carcinogenesis and cancer therapy that suggests PH-GPx as a potentially important enzyme involved in the control of this processes.