Ectopic lymphoid structures develop at sites of chronic inflammation and are generally thought to be beneficial in the control of cancer. Pikarsky and colleagues show that these structures can instead nurture liver tumor progenitor cells. Ectopic lymphoid-like structures (ELSs) are often observed in cancer, yet their function is obscure. Although ELSs signify good prognosis in certain malignancies, we found that hepatic ELSs indicated poor prognosis for hepatocellular carcinoma (HCC). We studied an HCC mouse model that displayed abundant ELSs and found that they constituted immunopathological microniches wherein malignant hepatocyte progenitor cells appeared and thrived in a complex cellular and cytokine milieu until gaining self-sufficiency. The egress of progenitor cells and tumor formation were associated with the autocrine production of cytokines previously provided by the niche. ELSs developed via cooperation between the innate immune system and adaptive immune system, an event facilitated by activation of the transcription factor NF-κB and abolished by depletion of T cells. Such aberrant immunological foci might represent new targets for cancer therapy.

Death rates from hepatocellular carcinoma (HCC) are steadily increasing, yet therapeutic options for advanced HCC are limited. We identify a subset of mouse and human HCCs harboring VEGFA genomic amplification, displaying distinct biologic characteristics. Unlike common tumor amplifications, this one seems to work via heterotypic paracrine interactions; stromal VEGF receptors (VEGFR), responding to tumor VEGF-A, produce hepatocyte growth factor (HGF) that reciprocally affects tumor cells. VEGF-A inhibition results in HGF downregulation and reduced proliferation, specifically in amplicon-positive mouse HCCs. Sorafenib—the first-line drug in advanced HCC—targets multiple kinases, including VEGFRs, but has only an overall mild beneficial effect. We found that VEGFA amplification specifies mouse and human HCCs that are distinctly sensitive to sorafenib. FISH analysis of a retrospective patient cohort showed markedly improved survival of sorafenib-treated patients with VEGFA-amplified HCCs, suggesting that VEGFA amplification is a potential biomarker for HCC response to VEGF-A–blocking drugs. Significance: Using a mouse model of inflammation-driven cancer, we identified a subclass of HCC carrying VEGFA amplification, which is particularly sensitive to VEGF-A inhibition. We found that a similar amplification in human HCC identifies patients who favorably responded to sorafenib—the first-line treatment of advanced HCC—which has an overall moderate therapeutic efficacy. Cancer Discov; 4(6); 730–43. ©2014 AACR. See related commentary by Luo and Feng, p. 640 This article is highlighted in the In This Issue feature, p. 621