Increased epidermal growth factor receptor (EGFR) gene copy number is strongly associated with EGFR mutations and adenocarcinoma in non-small cell lung cancers: a chromogenic in situ hybridization study of 182 patients.

SUMMARY: To evaluate the association of epidermal growth factor receptor (EGFR) gene copy number with EGFR and k-ras mutation status and tyrosine kinase inhibitor (TKI) sensitivity in non-small cell lung cancer (NSCLC), EGFR gene copy number of 182 NSCLC tumor specimens were analyzed by chromogenic in situ hybridization (CISH). EGFR and k-ras mutation analyses were also performed for, respectively, 176 and 157 of the 182 patients. Additionally, 36 patients in this study had received TKI monotherapy. The tumor was considered to be CISH positive if the gene copy number was >or=5 signals per nucleus in >or=40% of tumor cells. CISH-positive tumors were strongly associated with adenocarcinoma (56.8%) compared with squamous cell carcinoma (15.9%) (p<0.0001). The CISH-positive tumors were also strongly associated with EGFR mutations (78%) compared with wild type (20.2%) (p<0.0001). Only six tumors had k-ras mutations. None had EGFR mutation and only one was CISH positive. In the patients treated with TKI, EGFR mutation was strongly associated with TKI responsiveness (22/25 responders) (p<0.0001), but the CISH-positive tumors were only marginally significant (18/25 responders) (p=0.0665). Patients with EGFR mutations or CISH-positive tumors were all associated with longer median survival, although not statistically significant. Our results suggest Increased EGFR copy number was highly correlated with EGFR mutation in adenocarcinoma. Although it is less correlated with TKI responsiveness when compared with EGFR mutations, it still could be a good alternative molecular predictive marker for TKI responsiveness, since CISH can be done on paraffin section and is much quicker than DNA sequencing.

Complex mutation patterns of epidermal growth factor receptor gene associated with variable responses to gefitinib treatment in patients with non-small cell lung cancer.

Mutational analysis was performed in the kinase domain (exons 18-21) of the EGFR gene on tumor tissues of 65 non-small cell lung cancer (NSCLC) patients who had received gefitinib monotherapy. The association between EGFR gene mutation, gefitinib treatment response, and the overall survival were evaluated. In total, EGFR mutations with complex patterns were identified in 32 tumors. The overall mutation rate was 49.2% (32/65). Twenty of the 32 patients were responders, 10 non-responders, and 2 not assessable. The most common mutation in non-responders was L858R. Gefitinib responsiveness was only significantly associated with EGFR mutation and adenocarcinoma. The median survival for responder (15.5 months) was much longer than non-responder (9.23 months), though the difference only had marginal significance (p=0.056). The difference of overall survival between patients with and without EGFR mutation was non-significant (p=0.7819), mainly due to the short survival of the non-responders with EGFR mutations (median survival=6.2 months). Our study revealed that the response to gefitinib treatment in NSCLC patients with EGFR mutations could be quite variable even for the same EGFR mutation type. An analysis of the various EGFR mutations and the response patterns was also performed and compared with recently published reports on EGFR mutation and gefitinib responsiveness.

USP6 and CDH11 oncogenes identify the neoplastic cell in primary aneurysmal bone cysts and are absent in so-called secondary aneurysmal bone cysts.

Aneurysmal bone cyst (ABC) is a locally recurrent bone lesion that has been regarded as a reactive process. Recently, a neoplastic basis in primary ABC was evidenced by demonstration of clonal chromosome band 17p13 translocations that place the USP6 (TRE2 or TRE17) oncogene under the regulatory influence of the highly active CDH11 promoter. Herein, we report CDH11 and/or USP6 rearrangements in 36 of 52 primary ABCs (69%), of which 10 had CDH11-USP6 fusion, 23 had variant USP6 rearrangements without CDH11 rearrangement, and three had variant CDH11 rearrangements without USP6 rearrangement. USP6 and CDH11 rearrangements were restricted to spindle cells in the ABC and were not found in multinucleated giant cells, inflammatory cells, endothelial cells, or osteoblasts. CDH11 and USP6 rearrangements did not correlate with recurrence-free survival, or with other clinicopathological features. CDH11 and USP6 rearrangements were not found in any of 17 secondary ABC associated with giant cell tumor, chondroblastoma, osteoblastoma, and fibrous dysplasia. These findings demonstrate that primary ABC are mesenchymal neoplasms exhibiting USP6 and/or CDH11 oncogenic rearrangements. By contrast, secondary ABC lack CDH11 and USP6 rearrangements, and although morphological mimics of primary ABC, appear to represent a non-specific morphological pattern of a diverse group of non-ABC neoplasms.

Overexpression, amplification, and androgen regulation of TPD52 in prostate cancer.

Gains in the long arm of chromosome 8 (8q) are believed to be associated with poor outcome and the development of hormone-refractory prostate cancer. Based on a meta-analysis of gene expression microarray data from multiple prostate cancer studies (D. R. Rhodes et al., Cancer Res 2002;62:4427-33), a candidate oncogene, Tumor Protein D52 (TPD52), was identified in the 8q21 amplicon. TPD52 is a coiled-coil motif-bearing protein, potentially involved in vesicle trafficking. Both mRNA and protein levels of TPD52 were highly elevated in prostate cancer tissues. Array comparative genomic hybridization and amplification analysis using single nucleotide polymorphism arrays demonstrated increased DNA copy number in the region encompassing TPD52. Fluorescence in situ hybridization on tissue microarrays confirmed TPD52 amplification in prostate cancer epithelia. Furthermore, our studies suggest that TPD52 protein levels may be regulated by androgens, consistent with the presence of androgen response elements in the upstream promoter of TPD52. In summary, these findings suggest that dysregulation of TPD52 by genomic amplification and androgen induction may play a role in prostate cancer progression.

USP6 (Tre2) fusion oncogenes in aneurysmal bone cyst.

Aneurysmal bone cyst (ABC) is a locally aggressive osseous lesion that typically occurs during the first two decades of life. ABC was regarded historically as a nonneoplastic process, but recent cytogenetic data have shown clonal rearrangements of chromosomal bands 16q22 and 17p13, indicating a neoplastic basis in at least some ABCs. Herein we show that a recurring ABC chromosomal translocation t(16;17)(q22;p13) creates a fusion gene in which the osteoblast cadherin 11 gene (CDH11) promoter region on 16q22 is juxtaposed to the entire ubiquitin-specific protease USP6 (Tre2) coding sequence on 17p13. CDH11-USP6 fusion transcripts were demonstrated only in ABC with t(16;17) but other ABCs had CDH11 or USP6 rearrangements resulting from alternate cytogenetic mechanisms. CDH11 is expressed strongly in bone, and our findings implicate a novel oncogenic mechanism in which deregulated USP6 transcription results from juxtaposition to the highly active CDH11 promoter.

Cavernous sinus and leptomeningeal metastases arising from a squamous cell carcinoma of the face: case report.

OBJECTIVE AND IMPORTANCE: Invasion of trigeminal and facial perineural spaces is a recognized complication of cutaneous malignancies. Centripetal spread along the trigeminal nerve axis and into the cavernous sinus and the gasserian ganglion is rare. Metastasis to the leptomeninges and cauda equina has not been reported. We report a unique case of perineural spread and central dissemination from an epithelial squamous cell carcinoma (SCC) associated with a tumor biomarker. CLINICAL PRESENTATION: After excision of multiple cutaneous SCCs and basal cell carcinomas of the head and neck, a 70-year-old male patient developed successive, right-side, V1 and V2 trigeminal neuropathies and complete right cavernous sinus syndrome during a 5-year period. Concurrently, the right face became paralyzed. Left facial paresis developed during the latter half of this period. Two months before admission, subacute left lower-extremity radicular weakness resulted in falls. Serial magnetic resonance imaging scans obtained in the previous 4 years were unrevealing. At the time of admission, enhancing masses were found in the 1) right cavernous sinus and dura, foramina ovale and rotundum, and Meckel's cave, 2) right subtemporal region and orbital rectus muscles, and 3) cauda equina. Cerebrospinal fluid analysis demonstrated mild pleocytosis and rare carcinoma cells. INTERVENTION: Biopsy of the right cavernous sinus mass confirmed moderately differentiated, metastatic SCC. Immunohistochemical staining and fluorescence in situ hybridization revealed epidermal growth factor receptor overexpression and genomic amplification. CONCLUSION: The indolent progression of cranial nerve palsy among patients with resected cutaneous SCCs of the head and neck must raise clinical suspicion of perineural spread, even in the absence of radiological changes. Biomarkers predicting aggressive SCC behavior, illustrated here by epidermal growth factor receptor amplification and central invasion, have the potential to guide early therapy.

Correlation of MYCN amplification with MCM7 protein expression in neuroblastomas: a chromogenic in situ hybridization study in paraffin sections.

Amplification of the MYCN oncogene in neuroblastomas is generally associated with a more aggressive clinical course. Recently, 1 of the minichromosome maintenance proteins, MCM7, was found to be a direct target of the MYCN transcription factor in neuroblastoma. To confirm this correlation, chromogenic in situ hybridization (CISH) to detect MYCN amplification and immunohistochemical staining for MCM7 protein expression were performed on paraffin tissue sections of 26 neuroblastomas cases and of 4 recurrences of these tumors. Seven of the primary tumors showed MYCN amplification, and all were stage 3 or 4 tumors. Only 4 of these showed MCM7 overexpression. However, 11 primary tumors overexpressed MCM7. The 4 patients with MCM7 expression associated with MYCN amplification all died from the tumor. In contrast, the 7 patients with MCM7 overexpression but no MYCN amplification were all younger than 1 year of age and have shown good survival. This suggests that MCM7 overexpression by itself is not related to a poorer prognosis as is MYCN amplification. In addition, the 4 pairs of primary and recurrent tumors all showed changes in MCM7 expression from negative to positive, whereas none of them had MYCN amplification. This study showed that MCM7 overexpression is not necessarily correlated with MYCN amplification or an aggressive clinical course. Interpretation of the results of CISH was quite easy and straightforward because the preparations were viewed with an ordinary light microscope with good preservation of the tissue morphology.

Cloning of an Alpha-TFEB fusion in renal tumors harboring the t(6;11)(p21;q13) chromosome translocation.

MITF, TFE3, TFEB, and TFEC comprise a transcription factor family (MiT) that regulates key developmental pathways in several cell lineages. Like MYC, MiT members are basic helix-loop-helix-leucine zipper transcription factors. MiT members share virtually perfect homology in their DNA binding domains and bind a common DNA motif. Translocations of TFE3 occur in specific subsets of human renal cell carcinomas and in alveolar soft part sarcomas. Although multiple translocation partners are fused to TFE3, each translocation product retains TFE3's basic helix-loop-helix leucine zipper. We have identified the genes fused by the chromosomal translocation t(6;11)(p21.1;q13), characteristic of another subset of renal neoplasms. In two primary tumors we found that Alpha, an intronless gene, rearranges with the first intron of TFEB, just upstream of TFEB's initiation ATG, preserving the entire TFEB coding sequence. Fluorescence in situ hybridization confirmed the involvement of both TFEB and Alpha in this translocation. Although the Alpha promoter drives expression of this fusion gene, the Alpha gene does not contribute to the ORF. Whereas TFE3 is typically fused to partner proteins in subsets of renal tumors, we found that wild-type, unfused TFE3 stimulates clonogenic growth in a cell-based assay, suggesting that dysregulated expression, rather than altered function of TFEB or TFE3 fusions, may confer neoplastic properties, a mechanism reminiscent of MYC activation by promoter substitution in Burkitt's lymphoma. Alpha-TFEB is thus identified as a fusion gene in a subset of pediatric renal neoplasms.