Background and Aims: Hepatocholangiocarcinomas (H-ChCs), are mixed primary tumors of the liver, defined by the presence of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) components that may display stem cell features. Accordingly, H-ChC represents the most illustrative heterogeneous liver malignancies. Its tumoral heterogeneity hampers molecular analysis that may provide various signatures according to the area analyzed. The aim of this study was to assess the peptidic profiles of the different morphological patterns constitutive of H-ChC by MALDI imaging, an in situ approach able to connect molecular profiles with specific histological features, without preliminary step of molecular extraction or labeling. Method: MALDI imaging (RapifleX and Autoflex III MALDI, Bruker Daltonik GmbH) was applied on paraffin tumor sections of tissues microarrays (TMAs) built from 60 surgical cases of H-ChC. Entire tissue sections of selected cases were also analyzed (10 cases). Peptidic spectra were obtained from the different tumor patterns constitutive of H-ChC as well as from CC (n=29) and HCC (n=23) and the most discriminant peaks were identified. Results: Rich peptides spectra were obtained from all tumor cases tested, with more than 90 peptides peaks identified. The comparison of the relative intensities of each m/z value (peptidic peak) between the three tumor types (H-ChC, HCC, CC) revealed 19 discriminant peaks exhibiting a statistical significance. They showed a receiver operating curve (ROC) curve superior to 0.7 in the identification of H-ChCs when applied on cases and controls (Example, peak 1466 in figure 1). Comparative analysis of H-ChC cases showed great heterogeneity (1) from case to case (Fig.1 lanes 1 and 2 compared to lanes 3 to 5), (2) within case from different areas of the tumor (Fig.1 lanes 2 and 3), and (3) within case from a single tumor area (Fig.1 lane 1). Conclusion: This preliminary study demonstrates that MALDI imaging is a powerful tool for providing peptidic signatures from formalin fixed paraffin-embedded tumor samples. In addition, it confirms that H-ChCs are highly heterogeneous at the molecular level both at the inter and intratumoral scale. The identification of the proteins specifically associated with the different tumor components is currently ongoing. Fig. 1 Expression of m/z 1466 peak on a TMA. Each lane corresponds to a H-ChC case. A) Optical image, B) ion density map of peak 1466, C) magnification of core 5, showing an enhanced intensity of m/z 1466 in specific tumoral zones D) optical image, core 5, tumoral zones are highlighted in red discontinuous line.
Maldi imaging of hepatocholangiocarcinomas: A clue to tackle tumor heterogeneity preliminary results
Casadonte R;
2018-01-01
Abstract
Background and Aims: Hepatocholangiocarcinomas (H-ChCs), are mixed primary tumors of the liver, defined by the presence of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) components that may display stem cell features. Accordingly, H-ChC represents the most illustrative heterogeneous liver malignancies. Its tumoral heterogeneity hampers molecular analysis that may provide various signatures according to the area analyzed. The aim of this study was to assess the peptidic profiles of the different morphological patterns constitutive of H-ChC by MALDI imaging, an in situ approach able to connect molecular profiles with specific histological features, without preliminary step of molecular extraction or labeling. Method: MALDI imaging (RapifleX and Autoflex III MALDI, Bruker Daltonik GmbH) was applied on paraffin tumor sections of tissues microarrays (TMAs) built from 60 surgical cases of H-ChC. Entire tissue sections of selected cases were also analyzed (10 cases). Peptidic spectra were obtained from the different tumor patterns constitutive of H-ChC as well as from CC (n=29) and HCC (n=23) and the most discriminant peaks were identified. Results: Rich peptides spectra were obtained from all tumor cases tested, with more than 90 peptides peaks identified. The comparison of the relative intensities of each m/z value (peptidic peak) between the three tumor types (H-ChC, HCC, CC) revealed 19 discriminant peaks exhibiting a statistical significance. They showed a receiver operating curve (ROC) curve superior to 0.7 in the identification of H-ChCs when applied on cases and controls (Example, peak 1466 in figure 1). Comparative analysis of H-ChC cases showed great heterogeneity (1) from case to case (Fig.1 lanes 1 and 2 compared to lanes 3 to 5), (2) within case from different areas of the tumor (Fig.1 lanes 2 and 3), and (3) within case from a single tumor area (Fig.1 lane 1). Conclusion: This preliminary study demonstrates that MALDI imaging is a powerful tool for providing peptidic signatures from formalin fixed paraffin-embedded tumor samples. In addition, it confirms that H-ChCs are highly heterogeneous at the molecular level both at the inter and intratumoral scale. The identification of the proteins specifically associated with the different tumor components is currently ongoing. Fig. 1 Expression of m/z 1466 peak on a TMA. Each lane corresponds to a H-ChC case. A) Optical image, B) ion density map of peak 1466, C) magnification of core 5, showing an enhanced intensity of m/z 1466 in specific tumoral zones D) optical image, core 5, tumoral zones are highlighted in red discontinuous line.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
