Andrew Erickson's dissertation improves the outcome prediction of prostate cancer

The main aim of M.Sc. Andrew Erickson’s thesis entitled "In Search of Improved Outcome Prediction of Prostate Cancer – A Biological and Clinical Approach” was to identify novel biological and clinical factors that could be utilized in the outcome prediction of prostate cancer. His doctoral dissertation will be publically examined on Friday, 11 May, with the permission of the Faculty of Medicine of the University of Helsinki.

Prostate cancer is the most commonly diagnosed male cancer in Finland and accounts for approximately 30% of all new cancer diagnoses of Finnish men. Most men diagnosed with prostate cancer do not, however, die due to the disease. Current clinical treatments can have serious side effects and should only be offered to high-risk patients. Thus there is a great need for better prognostication of patients into more accurate risk-categories.

The main aim of M.Sc. Andrew Erickson’s thesis was to identify novel biological and clinical factors that could be utilized in the outcome prediction of prostate cancer. The thesis has been supervised by Docent Tuomas Mirtti and Associate Professor Antti Rannikko.

Andrew completed his Bachelor’s studies in the Pacific University, US, having molecular biology as his major subject. Andrew’s mother has Finnish roots and after graduation, Andrew decided that he wanted to live in Europe for a few years. The TRANSMED programme of the University of Helsinki was very appealing to him, since during his studies he had developed a keen interest in applied medical research.

He was accepted and started his Master’s studies in 2011.  Already during the next summer he started working as a research assistant at FIMM with Tuomas Mirtti who was coordinating the sample collection of urological biobank.

When Tuomas offered me a PhD thesis project with a focus on improving the outcome prediction of prostate cancer, my future plans changed. I was convinced that both the importance of the topic and the possibilities that the Finnish health care system has to offer for prospective clinical research were definitely worth spending the next few years here in Finland.

- Andrew Erickson

Andrew’s thesis consists of four publications, all of which have already been published. The first part of the thesis focuses on outcomes of low-risk active surveillance patients.

The most important novel metrics developed in the thesis is called a cumulative number of cancer locations (CCLO). It is a relatively simple but previously overlooked metric calculated by summing the cancer positive locations from two biopsy samples taken during the active surveillance phase.

Andrew was able to show that high CCLO predicts poor patient outcome. The results were repeated in two independent study cohorts.

For me personally, this study is the most important. The peer-review process was very long but also beneficial for the study. What started from a single cohort and a conference presentation ended up to be a large international multi-center study.

In addition to studying CCLO, Andrew utilized immunohistochemistry and analysed expression of two protein biomarkers on biopsies taken at the time of diagnosis. Loss of protein called PTEN was shown to predict poor outcome.

Our results suggest that PTEN stainings should be performed on diagnostic biopsies, and if PTEN loss is found, radical interventions should be considered.

In the second part of the thesis, the focus was on the long-term outcome of primarily treated patients. Also in this setting, loss of PTEN expression was shown to be associated with poorer outcome. Furthermore, comparing two different Gleason grade scaling systems provided evidence of Grade group outperforming Gleason score in predicting patient outcomes.

Andrew has been able to finish his PhD project in a notably short time but it has required a lot of efficiency and working long hours. He likes to make long term plans and is dedicated to building an independent research career in the future, ideally in Finland. He has already started his post-doctoral project at the Johns Hopkins University in Baltimore but will definitely continue collaborating with the clinicians here in Finland.

The public examination of Andrew Erickson’s doctoral dissertation will take place on 11 May at 12 o'clock noon in Lecture hall 2 of Haartman Institute (Haartmaninkatu 3). M.D., Ph.D. Mark Rubin, University of Bern, will serve as the opponent, and Professor Olli Carpen as the custos.

The dissertation is also available in an electronic form