RESUMO
Immunohistochemistry (IHC) is a widely-tested, low-cost and rapid ancillary technique available in all laboratories of pathology. This method is generally used for diagnostic purposes, but several studies have investigated the sensitivity and specificity of different immunohistochemical antibodies as a surrogate test in the determination of predictive biomarkers in non-small cell lung cancer (NSCLC), particularly for Epidermal Growth Factor Receptor (EGFR) gene mutations, Anaplastic Lymphoma Kinase (ALK) gene and ROS1 rearrangements. In this review, a critical examination of the works comparing the consistency of IHC expression and conventional molecular techniques to identify genetic alterations with predictive value in NSCLC is discussed. Summarizing, data on sensitivity and specificity of antibodies against ALK and ROS1 are very consistent and time has come to trust in IHC at least as a cost-effective screening tool to identify patients with rearranged tumors in clinical practice. On the other hand, mutant-specific antibodies against EGFR demonstrate a good specificity but a lowto- fair sensitivity, raising some cautions on their employment as robust predictive biomarkers. A brief comment on preliminary experiences with antibodies against BRAF, RET, HER2 and c-MET is also included.
Assuntos
Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Imuno-Histoquímica/métodos , Neoplasias Pulmonares/diagnóstico , Quinase do Linfoma Anaplásico , Biomarcadores Tumorais/imunologia , Carcinoma Pulmonar de Células não Pequenas/genética , Receptores ErbB/genética , Receptores ErbB/imunologia , Rearranjo Gênico , Predisposição Genética para Doença , Humanos , Imuno-Histoquímica/economia , Neoplasias Pulmonares/genética , Mutação , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/imunologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/imunologia , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/imunologia , Sensibilidade e EspecificidadeRESUMO
AIMS: To analyse the expression of several mucins (MUC1, MUC2, MUC3, MUC5AC and MUC6), epidermal growth factor receptor (EGFR), v-erb-b2 erythroblastic leukaemia viral oncogene homologue 2 (HER2), thyroid transcription factor-1 (TTF-1), caudal type homeobox 2 (CDX2) and cytokeratin 20 (CK20), and the presence of mutations of EGFR, KRAS and HER2 in congenital pulmonary airway malformations (CPAM). METHODS AND RESULTS: Forty-one cases of CPAM and six pulmonary sequestrations were included. TTF-1 expression was observed in all cases but was not seen in mucinogenic growths in CPAM. CDX2 expression was completely negative. MUC1 expression was noted in 12 (29%) CPAM and in 33% sequestrations. MUC5AC was noted in only five cases (26%) by immunohistochemistry and was found in the mucinogenic proliferations of type 1 CPAM. No immunolabelling was noted for the other mucins. EGFR was expressed variably in almost all cases, while HER2 and CK20 was seen exclusively in the mucinogenic proliferations. All mucinous growths were characterized by KRAS mutations. No EGFR and HER2 gene alterations were identified. CONCLUSIONS: KRAS mutations and MUC5AC, CK20 and HER2 expression was seen in all mucinogenic proliferations, supporting the neoplastic nature of these cytologically bland growths. These findings emphasize the importance of complete surgical resection of such lesions.