Allelic deletions involving chromosome 18q occur in more than 70 percent of colorectal cancers. Such deletions are thought to signal the existence of a tumor suppressor gene in the affected region, but until now a candidate suppressor gene on this chromosomal arm had not been identified. A contiguous stretch of DNA comprising 370 kilobase pairs (kb) has now been cloned from a region of chromosome 18q suspected to reside near this gene. Potential exons in the 370-kb region were defined by human-rodent sequence identities, and the expression of potential exons was assessed by an "exon-connection" strategy based on the polymerase chain reaction. Expressed exons were used as probes for cDNA screening to obtain clones that encoded a portion of a gene termed DCC; this cDNA was encoded by at least eight exons within the 370-kb genomic region. The predicted amino acid sequence of the cDNA specified a protein with sequence similarity to neural cell adhesion molecules and other related cell surface glycoproteins. While the DCC gene was expressed in most normal tissues, including colonic mucosa, its expression was greatly reduced or absent in most colorectal carcinomas tested. Somatic mutations within the DCC gene observed in colorectal cancers included a homozygous deletion of the 5′ end of the gene, a point mutation within one of the introns, and ten examples of DNA insertions within a 0.17-kb fragment immediately downstream of one of the exons. The DCC gene may play a role in the pathogenesis of human colorectal neoplasia, perhaps through alteration of the normal cell-cell interactions controlling growth.

Treating ovarian cancer in mouse models with inhibitors for the epigenetic regulators EZH2 and DNMT1 increases the expression of the inflammatory chemokines CXCL9 and CXCL10, resulting in enhanced tumour infiltration by effector T cells, and slowed tumour progression. The therapeutic response of cancer patients to immunotherapy can be variable. Weiping Zou and colleagues hypothesize that immunoprotective signature genes might be epigenetically silenced in cancer, thereby promoting cancer progression and blunting the clinical response to immunotherapy. To test this idea the authors treated ovarian cancer in mouse models with agents that inhibit the epigenetic regulators EZH2 and DNMT1. They find that inhibition of EZH2 and DNMT1 increases the expression of the inflammatory chemokines CXCL9/10, resulting in enhanced tumour infiltration by effector T cells, and slower tumour progression. Epigenetic silencing including histone modifications and DNA methylation is an important tumorigenic mechanism1. However, its role in cancer immunopathology and immunotherapy is poorly understood. Using human ovarian cancers as our model, here we show that enhancer of zeste homologue 2 (EZH2)-mediated histone H3 lysine 27 trimethylation (H3K27me3) and DNA methyltransferase 1 (DNMT1)-mediated DNA methylation repress the tumour production of T helper 1 (TH1)-type chemokines CXCL9 and CXCL10, and subsequently determine effector T-cell trafficking to the tumour microenvironment. Treatment with epigenetic modulators removes the repression and increases effector T-cell tumour infiltration, slows down tumour progression, and improves the therapeutic efficacy of programmed death-ligand 1 (PD-L1; also known as B7-H1) checkpoint blockade2,3,4 and adoptive T-cell transfusion5 in tumour-bearing mice. Moreover, tumour EZH2 and DNMT1 are negatively associated with tumour-infiltrating CD8+ T cells and patient outcome. Thus, epigenetic silencing of TH1-type chemokines is a novel immune-evasion mechanism of tumours. Selective epigenetic reprogramming alters the T-cell landscape6 in cancer and may enhance the clinical efficacy of cancer therapy.

Cervical cancer is a malignant epithelial tumor that forms in the uterine cervix. Most cases of cervical cancer are preventable through human papilloma virus (HPV) vaccination, routine screening, and treatment of precancerous lesions. However, due to inadequate screening protocols in many regions of the world, cervical cancer remains the fourth-most common cancer in women globally. The complete NCCN Guidelines for Cervical Cancer provide recommendations for the diagnosis, evaluation, and treatment of cervical cancer. This manuscript discusses guiding principles for the workup, staging, and treatment of early stage and locally advanced cervical cancer, as well as evidence for these recommendations. For recommendations regarding treatment of recurrent or metastatic disease, please see the full guidelines on NCCN.org.

Using a sensitive assay for RNA expression, we identified several abnormally spliced transcripts in which exons from a candidate tumor suppressor gene (DCC) were scrambled during the splicing process in vivo. Cloning and sequencing of PCR-amplified segments of the abnormally spliced transcripts showed that exons were joined accurately at consensus splice sites, but in an order different from that present in the primary transcript. Four scrambled transcripts were identified, each involving a different pair of exons. The scrambled transcripts were found at relatively low levels in a variety of normal and neoplastic cells of rodent and human origin, primarily in the nonpolyadenylated component of cytoplasmic RNA. These results demonstrate that the splicing process does not always pair sequential exons in the order predicted from their positions in genomic DNA, thus creating a novel type of RNA product.

Ovarian carcinomas are a heterogeneous group of neoplasms and are traditionally subclassified based on type and degree of differentiation. Although current clinical management of ovarian carcinoma largely fails to take this heterogeneity into account, it is becoming evident that each major histological type has characteristic genetic defects that deregulate specific signaling pathways in the tumor cells. Moreover, within the most common histological types, the molecular pathogenesis of low-grade versus high-grade tumors appears to be largely distinct. Mouse models of ovarian carcinoma have been developed that recapitulate many of the morphological features, biological behavior, and gene-expression patterns of selected subtypes of ovarian cancer. Such models will likely prove useful for studying ovarian cancer biology and for preclinical testing of molecularly targeted therapeutics, which may ultimately lead to better clinical outcomes for women with ovarian cancer.