Structured Abstract
Introduction
The detection of mutations in the epidermal growth factor receptor (EGFR) gene, which predict sensitivity to treatment with EGFR tyrosine kinase inhibitors (TKIs), represents a major advance in the treatment of lung adenocarcinoma. KRAS mutations confer resistance to EGFR -TKIs. The prevalence of these mutations in African-American patients has not been thoroughly investigated.
Methods
We collected formalin-fixed, paraffin-embedded material from resected lung adenocarcinomas from African-American patients at three institutions for DNA extraction. The frequencies of EGFR exon 19 deletions, exon 21 L858R substitutions and KRAS mutations in tumor specimens from African-American patients were compared to data in Caucasian patients (n=476).
Results
EGFR mutations were detected in 23 of the 121 specimens from African-American patients (19%, 95% CI 13–27%), while KRAS mutations were found in 21 (17%, 95% CI 12−25%). There was no significant difference between frequencies of EGFR mutations comparing African-American and Caucasian patients, 19% vs. 13% (61/476, 95% CI 10–16%) (p=0.11). KRAS mutations were more likely among Caucasians, 26% (125/476, 95% CI 23−30%) (p=0.04).
Conclusions
This is the largest study to date examining the frequency of mutations in lung adenocarcinomas in African-Americans. Although KRAS mutations were somewhat less likely, there was no difference between the frequencies of EGFR mutations in African-American patients as compared to Caucasians. These results suggest that all patients with advanced lung adenocarcinomas should undergo mutational analysis prior to initiation of therapy.
Adult T-cell leukemia/lymphoma (ATLL) is caused by the HTLV-1 virus, endemic to Japan and the Caribbean, and is likely derived from cells with the T-regulatory phenotype. The malignant cells express IL2 receptor α (CD25), and the majority express transcription factor Forkhead box P3 (Foxp3), in addition to T-cell markers. Occasional cases express CD30. Whereas Japanese cases are predominantly of the acute and chronic leukemic types, the less well-studied Caribbean cases are more often lymphomatous. We performed immunohistochemical analysis for CD25, Foxp3, and CD30 on samples from 42 US/Caribbean ATLL patients and correlated these markers with morphologic subtype and clinical characteristics. In the 16/42 patients who had successive biopsies, we determined the expression stability of these markers. Foxp3 was expressed in 26 of the 42 (62%) initial biopsies, and its intensity correlated with CD25 expression. It was more frequent in pleomorphic small-sized and medium-sized cell types than in large cell tumors but did not correlate with patients' clinical attributes. Foxp3 expression and morphology were unchanged in successive biopsies in 13 of 16 patients. Four initial biopsies had features of anaplastic large cell T lymphomas, all of which were Foxp3. Successive biopsies from 2 patients with pleomorphic medium cell variant showed diminishing expression of originally weak Foxp3 expression and de novo CD30 expression, whereas they showed morphologic progression to the anaplastic cell variant. A third patient's second biopsy revealed progression from pleomorphic medium to anaplastic large cell morphology with loss of Foxp3, but it remained CD30. Foxp3 expression correlates with pleomorphic small and medium cell types and may be lost with large cell transformation. The evolution of the latter type can be associated with the gain of CD30 expression; such ATLL tumors might respond to anti-CD30 monoclonal antibody therapies.
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