Precision medicine in rare tumors and the need for multicenter trials and international collaboratives: Sinonasal cancer as paradigm

The contemporary management of cancers of the sinonasal tract in adults

Sinonasal malignancies make up <5% of all head and neck neoplasms, with an incidence of 0.5-1.0 per 100,000. The outcome of these rare malignancies has been poor, whereas significant progress has been made in the management of other cancers. The objective of the current review was to describe the incidence, causes, presentation, diagnosis, treatment, and recent developments of malignancies of the sinonasal tract. The diagnoses covered in this review included sinonasal undifferentiated carcinoma, sinonasal adenocarcinoma, sinonasal squamous cell carcinoma, and esthesioneuroblastoma, which are exclusive to the sinonasal tract. In addition, the authors covered malignances that are likely to be encountered in the sinonasal tract-primary mucosal melanoma, NUT (nuclear protein of the testis) carcinoma, and extranodal natural killer cell/T-cell lymphoma. For the purpose of keeping this review as concise and focused as possible, sarcomas and malignancies that can be classified as salivary gland neoplasms were excluded.

Emerging concepts in sinonasal tumor research

PURPOSE OF REVIEW

Sinonasal malignancies are rare and understudied, often diagnosed at late stages, and may behave aggressively. This review explores investigative diagnostic, therapeutic, and scientific advances specific to sinonasal undifferentiated carcinoma (SNUC), intestinal-type adenocarcinoma (ITAC), and olfactory neuroblastoma (ONB).

RECENT FINDINGS

A number of studies have recently contributed more robust knowledge of the genetic and molecular landscapes of SNUC, ITAC, and ONB. These analyses have identified SMARCB1 and IDH2 mutations in SNUC, potentially allowing for the tumor's subdivision. Recent studies have also defined a role for induction chemotherapy in SNUC. Somatic mutations for ITAC have been identified and may be potentially targetable with FDA approved therapies. Studies defining the tumor microenvironment for ITAC and ONB have introduced the possibility of immune checkpoint inhibition for these tumor types.

SUMMARY

Studies reviewed here detail promising results of the most current and novel characterization of SNUC, ITAC, and ONB genetic and molecular landscapes, which have informed ongoing therapeutic discovery. With continued multi-institutional efforts, the field of sinonasal tumor research will achieve higher disease control and improved treatment outcomes for patients afflicted with these rare cancers.

Aberrant Signaling Pathways in Sinonasal Intestinal-Type Adenocarcinoma

Sinonasal intestinal-type adenocarcinoma (ITAC) is strongly related to occupational exposure to wood and leather dust, however, little is known on the genetic alterations involved in tumor development and progression. The aim of this study was to identify tumorigenic signaling pathways affected by gene mutations and their relation to clinical features. We applied whole exome sequencing of 120 cancer-related genes in 50 ITACs and analyzed the signaling activity of four specific pathways frequently affected by mutations. Genes involved in DNA damage response showed somatic mutations in 30% of cases, including four tumors that also harbored germline mutations. Genes in Wnt, MAPK and PI3K pathways harbored mutations in 20%, 20% and 24% of cases, respectively. Mutations and copy number gains in receptor tyrosine kinases possibly affecting MAPK and PI3K pathways occurred in 44% of cases. Expression of key pathway proteins showed no correlation to mutations in these pathways, except for nuclear β-catenin and APC/CTNNB1 mutation. No specific gene mutation, mutated pathway, nor pathway activity level showed correlation to clinical data or survival. In addition, a similar mutational profile was observed among histological subtypes. The wide spectrum of gene mutations suggests that ITAC is a genetically heterogeneous without specific characterizing gene mutations.