Interphase cytogenetic analysis of lung adenocarcinomas with bronchioloalveolar pattern

Aneuploidy has been suggested as a marker for stratification of many neoplasms but its potential usefulness in adenocarcinoma (ADC) with bronchioloalveolar (BAC) pattern has not been well defined. We examined paraffin-embedded tissue sections from 28 cases of ADC with BAC pattern as well as 7 benign lung lesions and 9 normal lung tissue samples for chromosomal aneu- ploidy by in situ hybridization using digoxigenin-labelled probes for chromosomes 1 and X. Of the 28 ADC with BAC pattern, 17 (61%) were diploid and 11 (39%) were aneuploid. Of the 17 diploid cases, 7 (41%) were male and 10 (59%) were female and of the 11 aneuploid cases, 2 (18%) were male, 9 (82%) were female. Regarding the cell type, 24 (86%) were adenocarcinomas in situ (AIS) so called BAC and minimally invasive ADC (MIA), and 4 cases (14%) were invasive ADC. Of the 12 cases each of AIS and MIA, 9 (75%) and 8 (67%) had diploid pattern respec- tively. Of the 4 invasive ADC cases, all had aneuploid pattern. Seventeen cases (71%) with T1 tumor size (>0 mm~≦30 mm), had diploid and 4 cases (100%) with T2 tumor size (>30 mm ≦70 mm) had aneuploid pattern. Statistical analyses showed that nuclear diploidy was significantly cor- related with AIS and MIA tumor types while aneuploidy correlated with invasive ADC type (P=0.025). Also a significant correlation was found between ploidy and tumor size (P=0.033). In conclusion, these findings suggest that DNA ploidy analysis provides useful information for the assessment of cellular kinetics and reflect histopathological subtypes in ADC with BAC pattern that are destined to behave aggressively.