RESUMO
Accurate classification of nonsmall cell lung cancers is of paramount clinical relevance, as novel chemotherapeutic agents show different efficacy in adenocarcinomas (ADCs) compared with squamous cell carcinomas (SQCCs). Cyto and histomorphology may sometimes be insufficient for this distinction and immunohistochemistry may improve diagnostic accuracy. The measurement of miR-205 may be another tool for the distinction between ADC and SQCC. The aim of our study was to compare morphologic and immunohistochemical classification with the relative quantification of miR-205 and miR-21 insurgically resected and well-characterized lung tumors (25 ADCs, 24 SQCCs, 1 adenosquamous). The miR-21 relative levels were similar in SQCC and ADC, whereas the miR-205 relative levels were lower in ADC (P<0.0001). The miR-205 sample score value, determined according to Lebanony et al, was higher in ADC (range, 2.8 to 9.08) compared with SQCC (range, -4.17 to 2.445) (P<0.0001). Accordingly, 22 tumors were classified as ADC and 28 tumors as SQCC, although 8 cases (2 SQCCs and 6 ADCs) were in the range of "near cutoff values." Four cases classified as SQCC (according to the sample score method) corresponded to cases classified as ADC on the basis of morphoimmunohistochemical evaluation. In conclusion, the relative quantification of miR-205 and miR-21 seems to be a promising diagnostic tool. However, the molecular approach is still not completely satisfactory as it may misclassify a non-negligible percentage of cases. Therefore, it cannot be used as a substitute of accurate morphologic and immunophenotypical characterization of tumors, but could be used as an adjunctive diagnostic criterion in selected cases.
Assuntos
Adenocarcinoma/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma de Células Escamosas/diagnóstico , Neoplasias Pulmonares/diagnóstico , MicroRNAs/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Diagnóstico Diferencial , Feminino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , MicroRNAs/genética , RNA Neoplásico/análise , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Large cell carcinomas (LCCs) of the lung are heterogeneous and may be of different cell lineages. We analyzed 56 surgically resected lung tumors classified as LCC on the basis of pure morphologic grounds, using a panel of immunophenotypic markers (adenocarcinoma [ADC]-specific, thyroid transcription factor-1, cytokeratin 7, and napsin A; squamous cell carcinoma [SQCC]-specific, p63, cytokeratin 5, desmocollin 3, and Δnp63) and the quantitative analysis of microRNA-205 (microRNA sample score [mRSS]). Based on immunoprofiles 19 (34%) of the cases were reclassified as ADC and 14 (25%) as SQCC; 23 (41%) of the cases were unclassifiable. Of these 23 cases, 18 were classified as ADC and 5 as SQCC according to the mRSS. Our data show that an extended panel of immunohistochemical markers can reclassify around 60% of LCCs as ADC or SQCC. However, a relevant percentage of LCCs may escape convincing immunohistochemical classification, and mRSS could be used for further typing, but its clinical relevance needs further confirmation.