Figure 1.
Detection of EML4-ALK translocation by nested RT-PCR.
Nested RT-PCR was performed using serially diluted cDNA from H2228 cells. As little as 7.8×10−4 ng cDNA could be used for consistent detection of the variant 3 fusion transcript with this protocol (Upper panel). Representative gel electrophoresis results for the nested RT-PCR (lower panel). Lane marker: 200-bp ladder; positive control: H2228; negative control: A549. Other lanes correspond to samples exhibiting the EML4-ALK translocation, labeled by case number.
Figure 2.
Schematic representation of fusion junctions and flanking sequences of the EML4-ALK fusion gene variants.
(A) variant 1, (B) variant 2, (C) variant 3.
Table 1.
NSCLC patient characteristics (N = 208).
Table 2.
Clinical features associated with EML4-ALK fusion gene-positive patients.
Table 3.
Clinical characteristics of genotype-specific subsets of NSCLC patients.
Figure 3.
The pathological analysis of EML4-ALK-rearranged lung cancer patients by H&E staining.
The primary tumors of Cases 1, 3, 4 and 5 showed the solid signet-ring cell pattern composed of solid growth with papillary (or micropapillary) or a signet-ring cell component, and other primary sites of Cases 2, 6 and 7 showed the mucinous cribriform pattern consisting of abundant extracellular mucus and cribriform structures. In the lymph node metastatic sites, solid signet-ring cell pattern was identified in Cases 1–5, and mucinous cribriform pattern was only seen in Case 6.
Figure 4.
The pathological analysis of EML4-ALK-rearranged lung cancer patients by ALK immunohistochemistry staining.
ALK-positive immunostaining was shown in primary tumors of all 7 ALK-rearranged lung cancer patients with diffuse staining in the cytoplasm. ALK-positive staining was not apparent in each primary tumor cell, especially in Case 4, which is an adenosquamous carcinoma with ALK positive staining only in the adenocarcinoma part, not in the squamous carcinoma component (indicated in red text: Adeno and Squamous). For the lymph node metastatic sites, Cases 2, 5 and 6 showed ALK-positive staining and Cases 1, 3 and 4 showed ALK-negative staining.
Figure 5.
The pathological analysis of EML4-ALK-rearranged lung cancer patients by ALK immunofluorescence staining.
ALK-positive immunostaining was shown in primary tumor of all 7 ALK-rearranged lung cancer patients. For the lymph node metastatic sites, Cases 2, 5 and 6 showed ALK-positive staining and Cases 1, 3 and 4 showed ALK-negative staining. These results were similar to those for ALK immunohistochemistry. ALK: green; Ki-67: red; DAPI: blue.
Figure 6.
Meta-analysis of data for EML4-ALK.
(A) Meta-analysis using a random effects model demonstrated that smoking status was significantly correlated with EML4-ALK translocation; (B) Meta-analysis of data using a fixed effects model indicated that adenocarcinoma (AD) significantly correlated with the EML4-ALK translocation. The translocation was significantly more frequent in the AD group than in the non-AD group; (C) Meta-analysis using a fixed effects model suggested that gender was not significantly correlated with EML4-ALK translocation frequency.
Table 4.
Data extracted from 14 studies included in the meta-analysis.