As part of the release of the Pathology Atlas, the Human Protein Atlas Blog presents brief and informative summaries of most cancers, and highlight genes with prognostic association in the different cancer forms. The Pathology Atlas is an open access database which includes quantitative transcriptomics data and spatial proteomics data of the major human cancer types that have been analyzed using a systems level approach.

We focus on prostate cancer in this week's blog post to highlight Prostate Cancer Awareness Month in North America and the European Prostate Cancer Awareness Day on the 27th of September.

Prostate cancer is one of the most common non-cutaneous malignancies in men worldwide. The majority of primary prostate cancer cases are adenocarcinomas and the incidence of prostate cancer in Sweden in 2015 was more than 10,000, while the estimated number of cases in the US for 2017 are expected to reach 160,000.

Prostate cancer develops in ageing men and the median age at diagnosis is 65-70 years. Most patients, especially those with localized tumors, often die of other complications without significant disability caused by the cancer. Approximately 15% of patients with prostate cancer are in high risk of disease-related symptoms and death. Despite this, many individuals may have prolonged survival even after the cancer has metastasized to distant sites.

The analysis of prognostic genes in prostate cancer was performed based on publicly available gene expression data and clinical metadata from the Cancer Genome Atlas (TCGA) consisting of 494 patients with different stages of prostate cancer. According to the analysis, 160 genes were associated with prognostic outcome, out of which 135 genes were associated with unfavourable prognosis and 25 genes with favourable prognosis.

The Outer dense fiber protein 2, encoded by the ODF2 gene, is a major component of sperm tail, important for the proper structure of the sperm tail. Previous reports has shown that ODF2 may be a crucial component of the microtubule organizing center. Defects in this gene have been linked to infertility and abnormal sperm morphology. In our analysis, higher expression of the ODF2 gene in prostate cancer patients is shown to be associated with unfavourable prognosis. Immunohistochemical staining of ODF2 shows a cytoplasmic expression pattern in prostate cancer samples (Figure 1).

The ATP6V1E1 gene encodes a multi-subunit enzyme important for acidification of organelles in eukaryotic cells. This process is deemed necessary for intracellular mechanisms such as protein sorting, zymogen activation and receptor-mediated endocytosis to name a few. In our analysis, higher expression of the ATP6V1E1 gene in prostate cancer patients is shown to be associated with favorable prognosis. Immunohistochemical staining of ATP6V1E1 shows a cytoplasmic expression pattern in prostate cancer samples (Figure 2).

Explore the Prostate cancer proteome and search for your gene of interest in our new Pathology Atlas! You can read more about this cancer form in the Prostate cancer - Dictionary and about other cancers in our blog posts on breast cancer and colon cancer.

If you missed the launch of the Pathology Atlas, you can read a summary here, and do not miss the related research article, published in last month in Science.

1. Uhlen et al "A Pathology Atlas of human cancer transcriptomes" Science (August 17, 2017) accessed online at: http://dx.doi.org/10.1126/science.aan2507

Feria Hikmet Noraddin