Project description:Background & Aims: The metastatic process is complex and remains a major obstacle in the management of colorectal cancer (CRC). To gain a better insight into the biologic events driving the metastatic process we investigated genomic aberrations in a large cohort of matched CRC primaries and distant metastases from various sites. Methods: In total, 62 primary colorectal cancers, 62 matched normal specimens, and 68 matched metastases (from liver, lung, ovary, omentum, and distant lymph nodes) were analyzed by high resolution array comparative genomic hybridization (array CGH) for DNA copy number changes. Findings were validated using a publicly available dataset consisting of 21 primary tumors and matched liver metastases. Fluorescence in situ hybridization (FISH) was used to confirm some of the DNA copy number changes observed. Results: Overall patterns of DNA copy number aberrations were highly similar between primary tumors and their metastases, confirming clonality. Additional copy number aberrations in metastasis are rare and rather than recurrent they were sporadic for individual patients. The only recurrent differences between primary tumors and their metastases were two chromosomal regions, 6q21 and 8q24.21 encompassing the MYC oncogene, that coamplified in three metastases of two patients (3.2%). FISH analysis confirmed the high level co-amplification in the metastasis, which were not detected in their primary tumors. Conclusions: Primary CRC and their metastases show highly similar patterns of DNA copy number changes, additional copy number aberrations in metastasis are rare and recurrences exceptional. These observations are consistent with the hypothesis that the metastatic potential is predestined early in the development of the primary tumor. In total, 62 primary colorectal cancers, 62 matched normal specimens, and 68 matched metastases (liver, lung, ovarian, omentum and distant lymph nodes) were analyzed by high resolution array comparative genomic hybridization (array CGH).

Project description:Metastatic disease remains one of the most urgent clinical challenges accounting for over 90% of cancer-related deaths. Yet, the identification of novel therapeutic targets to fight or prevent metastatic disease has been hampered by the limited availability of clinically relevant mouse models of metastasis formation. To address this caveat, we developed a novel preclinical mouse model of spontaneous metastatic breast cancer that recapitulates the key biological events of the metastatic cascade and mimics the clinical course of metastatic disease in humans. Exploiting the conditional K14cre;CdhF/F;Trp53F/F mouse model of de novo mammary tumor formation, we orthotopically transplanted K14cre;CdhF/F;Trp53F/F derived mouse invasive lobular carcinoma (mILC) fragments into mammary glands of wild-type syngeneic hosts. Once recipient mammary tumors were established, we mimicked the clinical setting and performed a mastectomy. Following surgery, recipient mice eventually succumbed to wide-spread clinically overt metastatic disease in lymph nodes, lungs and gastrointestinal tract. Using aCGH analyses, we explored the relationship between the genomic profiles of mammary donor tumors and paired recipient outgrowths and observed a strong correlation, indicating that the genomic profile of the parental K14cre;CdhF/F;Trp53F/F mILC is highly conserved in recipient mammary tumors. To investigate the genomic relationship between recipient mammary tumors and their metastases, we examined the correlation structure of genomic profiles derived from paired sets of primary tumors and metastases. Genomic profiles of clonally-related recipient mammary tumors were highly conserved in local and distant metastases, indicating that few genomic alterations occur during transition from a primary tumor to a distant site. To more thoroughly examine potential site-specific genomic alterations, we constructed so-called ‘delta-profiles’ by calculating the difference between the genomic profile of a recipient mammary tumor and its paired lymph node- and lung metastasis. Site-specific recurrent alterations were not observed in lymph node nor lung metastases. Taken together, these data show that genomic profiles of metastases are highly similar to those of parental recipient tumors and that, if changes occurred, they did not recur in different independent samples. We performed aCGH analyses on DNA isolated from K14cre;Cdh-/-;Trp53-/- derived donor mILCs (n=3) and their recipient mammary tumor outgrowths (n=10). Furthermore, we also analyzed genomic profiles derived from lung (n=10), tumor-draining (n=7) and distant lymph node metastases (n=5) isolated from the same recipient mice. DNA from each of these samples was hybridized against related donor splenic DNA.

Project description:Metastatic disease remains one of the most urgent clinical challenges accounting for over 90% of cancer-related deaths. Yet, the identification of novel therapeutic targets to fight or prevent metastatic disease has been hampered by the limited availability of clinically relevant mouse models of metastasis formation. To address this caveat, we developed a novel preclinical mouse model of spontaneous metastatic breast cancer that recapitulates the key biological events of the metastatic cascade and mimics the clinical course of metastatic disease in humans. Exploiting the conditional K14cre;CdhF/F;Trp53F/F mouse model of de novo mammary tumor formation, we orthotopically transplanted K14cre;CdhF/F;Trp53F/F derived mouse invasive lobular carcinoma (mILC) fragments into mammary glands of wild-type syngeneic hosts. Once recipient mammary tumors were established, we mimicked the clinical setting and performed a mastectomy. Following surgery, recipient mice eventually succumbed to wide-spread clinically overt metastatic disease in lymph nodes, lungs and gastrointestinal tract. Using aCGH analyses, we explored the relationship between the genomic profiles of mammary donor tumors and paired recipient outgrowths and observed a strong correlation, indicating that the genomic profile of the parental K14cre;CdhF/F;Trp53F/F mILC is highly conserved in recipient mammary tumors. To investigate the genomic relationship between recipient mammary tumors and their metastases, we examined the correlation structure of genomic profiles derived from paired sets of primary tumors and metastases. Genomic profiles of clonally-related recipient mammary tumors were highly conserved in local and distant metastases, indicating that few genomic alterations occur during transition from a primary tumor to a distant site. To more thoroughly examine potential site-specific genomic alterations, we constructed so-called ‘delta-profiles’ by calculating the difference between the genomic profile of a recipient mammary tumor and its paired lymph node- and lung metastasis. Site-specific recurrent alterations were not observed in lymph node nor lung metastases. Taken together, these data show that genomic profiles of metastases are highly similar to those of parental recipient tumors and that, if changes occurred, they did not recur in different independent samples.

Project description:Circulating tumor cells (CTCs) are critical in the development of distant organ tumor metastasis, and are associated with advanced cancer stage and poor patient outcome. Here, we present the first genome-wide nucleotide-level characterization of CTCs. Our single-nucleotide polymorphism (SNP) analysis in patients with melanoma involved: 1) global comparative genomic analysis of CTCs and matched regional metastases, 2) identification of key genomic aberrations in CTCs, 3) verification of these target genes in aggressive distant tumor metastases, and 4) evidence of selective expression and functional consequence of CTC-associated genes in melanomas. We report 131 aberrant loci in CTCs that are potentially pro-metastatic, and show that such expression of a 5-marker gene panel (CSMD2, CNTNAP5, FLJ14051, ADAM6, TRPM2) in melanomas confers prognostic utility. Successful treatment of melanoma requires understanding of the metastatic process and identification of patients with tumors most likely to develop aggressive metastatic disease. Melanomas are heterogeneous, and CTCs have long been recognized as vehicles for cancer spread, representing particularly aggressive tumor clones that can evolve into successful clinical metastases. Elucidation of genomic aberrations in CTCs will aid in the development of prognostic biomarkers and therapeutic strategies to target CTCs to prevent or control distant cancer spread. This study provides the first detailed genomic confirmation of the close relation between CTCs and tumor metastases, and illustrates how CTCs can be utilized as a novel approach and rational source for identification of pro-metastatic genes in cancer research. Three individual patient cohorts were utilized in the study. CNV and LOH loci were evaluated initially in metastatic melanoma patients (n=13) in a discovery cohort. SNP loci that harbored CNV/LOH in CTCs were then separately verified for: (a) presence in distant organ metastasis (AJCC Stage IV melanoma) (n=27), and (b) relevance to prognosis in regional melanoma metastasis (AJCC Stage III melanoma) (n=35). The first discovery patient cohort group was utilized for capture of CTCs, and consisted of peripheral blood mononuclear cell (PBMC) and tumor specimens from metastatic melanoma patients (n=13). CTC-related loci were verified in a second cohort of patients with Stage IV distant organ metastases (n=27), including 15 brain, 4 lung, and 8 gastrointestinal (bowel, liver) metastases. The third patient cohort consisted of early passage (<12) established melanoma cell lines derived from 35 regional melanoma metastases (Stage III) for evaluation of the prognostic utility of the CTC-associated aberrant loci.

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Specific genomic aberrations in squamous cell lung carcinoma with lymph node or distant metastasis

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