Updated Frequency of EGFR and KRAS Mutations in NonSmall-Cell Lung Cancer in Latin America: The Latin-American Consortium for the Investigation of Lung Cancer (CLICaP).

INTRODUCTION: Previously, we reported the frequency of epidermal growth factor receptor (EGFR) and KRAS mutations in nonsmall-cell lung cancer (NSCLC) patients in Latin America. The EGFR mutation frequency was found between Asian (40%) and Caucasian (15%) populations. Here, we report the updated distribution of NSCLC mutations. METHODS: A total of 5738 samples from NSCLC patients from Argentina (1713), Mexico (1417), Colombia (1939), Peru (393), Panama (174), and Costa Rica (102) were genotyped for EGFR and KRAS. RESULTS: The median patient age was 62.2 ± 12.3 years; 53.5% were women, 46.7% had a history of smoking, and 95.2% had adenocarcinoma histology. The frequency of EGFR mutations was 26.0% (95% confidence interval [CI], 24.9-27.1; Argentina, 14.4% [12.8-15.6]; México, 34.3% [31.9-36.7]; Colombia, 24.7% [22.8-26.6]; Peru, 51.1% [46.2-55.9]; Panamá, 27.3 [20.7-33.9]; and Costa Rica, 31.4% [22.4-40.4]). The frequency of KRAS mutations was 14.0% (9.1-18.9). In patients with adenocarcinoma, EGFR mutations were independently associated with gender (30.7% females vs. 18.4% males; p < 0.001), nonsmoker status (27.4% vs. 17.1%, p < 0.001), ethnicity (mestizo/indigenous, 35.3% vs. Caucasian, 13.7%, p < 0.001), and the absence of KRAS mutation (38.1% vs. 4.7%; p < 0.001). The overall response rate to EGFR tyrosine kinase inhibitors was 60.6% (95% CI, 52-69), with a median progression-free survival and overall survival of 15.9 (95% CI, 12.420.6) and 32 months (95% CI, 26.5-37.6), respectively. CONCLUSION: Our findings support the genetic heterogeneity of NSCLC in Latin America, confirming that the frequency of EGFR mutations is intermediate between that observed in the Asian and Caucasian populations.

Sequence analysis of mutations and translocations across breast cancer subtypes.

Breast carcinoma is the leading cause of cancer-related mortality in women worldwide, with an estimated 1.38 million new cases and 458,000 deaths in 2008 alone. This malignancy represents a heterogeneous group of tumours with characteristic molecular features, prognosis and responses to available therapy. Recurrent somatic alterations in breast cancer have been described, including mutations and copy number alterations, notably ERBB2 amplifications, the first successful therapy target defined by a genomic aberration. Previous DNA sequencing studies of breast cancer genomes have revealed additional candidate mutations and gene rearrangements. Here we report the whole-exome sequences of DNA from 103 human breast cancers of diverse subtypes from patients in Mexico and Vietnam compared to matched-normal DNA, together with whole-genome sequences of 22 breast cancer/normal pairs. Beyond confirming recurrent somatic mutations in PIK3CA, TP53, AKT1, GATA3 and MAP3K1, we discovered recurrent mutations in the CBFB transcription factor gene and deletions of its partner RUNX1. Furthermore, we have identified a recurrent MAGI3-AKT3 fusion enriched in triple-negative breast cancer lacking oestrogen and progesterone receptors and ERBB2 expression. The MAGI3-AKT3 fusion leads to constitutive activation of AKT kinase, which is abolished by treatment with an ATP-competitive AKT small-molecule inhibitor.

Frequent downregulation of the transcription factor Foxa2 in lung cancer through epigenetic silencing.

PURPOSE: We sought to determine the mechanisms of downregulation of the airway transcription factor Foxa2 in lung cancer and the expression status of Foxa2 in non-small-cell lung cancer (NSCLC). METHODS: A series of 25 lung cancer cell lines were evaluated for Foxa2 protein expression, FOXA2 mRNA levels, FOXA2 mutations, FOXA2 copy number changes and for evidence of FOXA2 promoter hypermethylation. In addition, 32 NSCLCs were sequenced for FOXA2 mutations and 173 primary NSCLC tumors evaluated for Foxa2 expression using an immunohistochemical assay. RESULTS: Out of the 25 cell lines, 13 (52%) had undetectable FOXA2 mRNA. The expression of FOXA2 mRNA and Foxa2 protein were congruent in 19/22 cells (p = 0.001). FOXA2 mutations were not identified in primary NSCLCs and were infrequent in cell lines. Focal or broad chromosomal deletions involving FOXA2 were not present. The promoter region of FOXA2 had evidence of hypermethylation, with an inverse correlation between FOXA2 mRNA expression and presence of CpG dinucleotide methylation (p < 0.0001). In primary NSCLC tumor specimens, there was a high frequency of either absence (42/173, 24.2%) or no/low expression (96/173, 55.4%) of Foxa2. In 130 patients with stage I NSCLC there was a trend towards decreased survival in tumors with no/low expression of Foxa2 (HR of 1.6, 95%CI 0.9-3.1; p = 0.122). CONCLUSIONS: Loss of expression of Foxa2 is frequent in lung cancer cell lines and NSCLCs. The main mechanism of downregulation of Foxa2 is epigenetic silencing through promoter hypermethylation. Further elucidation of the involvement of Foxa2 and other airway transcription factors in the pathogenesis of lung cancer may identify novel therapeutic targets.