Interestingly, variation in [11C]erlotinib accumulation in the primary tumor and metastatic sites within the same subject was observed, suggesting that a single biopsy may provide incomplete data for EGFR profiling, supporting the development of a [11C]erlotinib-based imaging procedure for EGFR status assessment (Figure 4b,c) [70]. This evidence concerns the gene EGFR and neoplasm.