The Key Role of Pathology in the Context of Precision Medicine Trials

Fig. 2.1

Example of a PTEN loss of expression validating a PTEN genomic loss. (a) Immunolabeling of PTEN protein (clone A2B1, Zymed® laboratories, CA, USA). The metastatic cells are PTEN negative in the presence of the positive expression of PTEN by the fibroblasts (internal positive control). (b) The SNP6.0 copy number profile shows a focal PTEN loss

Nuclear expression of PTEN has been reported but was not considered in the frame of the SHIVA trial for PTEN expression levels’ interpretation. The cutoff to consider a case positive was at least 10 % of positive cells with a weak intensity. In the SHIVA trial, 7 cases presented a PTEN deletion and 100 a PTEN loss. One hundred three cases were available for PTEN IHC analysis. In 56 out of the 103 analyzed cases (54 %), PTEN was not expressed, signing out the genomic loss (Fig 2.2).

Fig. 2.2

Example of a PTEN loss of expression validating a PTEN genomic deletion. (a) Immunolabeling of PTEN protein (clone A2B1, Zymed® laboratories, CA, USA). The metastatic cells are PTEN negative in the presence of the positive expression of PTEN by the fibroblasts (internal positive control). (b) The SNP6.0 copy number profile shows a focal PTEN deletion. (c) The external positive control represented by the intracytoplasmic positivity of the normal prostatic fibroblasts

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