Sami Blom's dissertation provides novel tools for analysis of tumor tissue in prostate cancer

Sami Blom's thesis entitled " Spatial Characterisation of Prostate Cancer by Multiplex Immunohistochemistry and Quantitative Image Analysis” will be publicly examined on Friday, 27 September, with the permission of the Faculty of Medicine of the University of Helsinki. The thesis presents the development of a novel multiplex Immunohistochemistry platform for quantitative analysis of tissue samples.

Prostate cancer is the most common cancer in men and the number of new diagnoses is steadily increasing. There is a big clinical need for biomarkers that could be used for providing more accurate prognostic information and selecting the most suitable treatment options for each prostate cancer patient. 

The main aim of M.Sc. Sami Blom’s thesis entitled "Spatial Characterisation of Prostate Cancer by Multiplex Immunohistochemistry and Quantitative Image Analysis” to be examined on September 27 was to develop new methods that could be used to provide better understanding of the complex biological mechanisms behind prostate cancer development. The thesis consists of three publications, all published in high-profile journals.

Sami Blom graduated from the University of Turku in 2011, with masters in biotechnology. Dr. Teijo Pellinen recruited him to FIMM thanks to a recommendation from Teijo’s former colleague. This introduction turned out to be quite a lucky shot and resulted in Sami starting his PhD project under the supervision of Teijo Pellinen and Professor Olli Kallioniemi in 2012.

The starting point of the thesis was the huge scientific need for a method that would combine the spatial resolution of standard immunohistochemistry, while overcoming its most critical limitation, capability to detect of only one protein at a time.

During the first few years of his thesis work, Sami focused on developing a novel multiplex Immunohistochemistry platform for quantitative analysis of formalin-fixed paraffin-embedded tissue samples. This platform allows simultaneous detection of six different biomarkers.  Combined with automated image analysis, the approach allows answering much more complex biological questions than what is possible with the traditional immunohistochemistry methods.

The platform, including tissue staining, imaging, and analysis methodology, is described in the first publication of Sami’s thesis. In addition, this paper demonstrated the feasibility of the approach by quantitative analysis of epithelial cells and immune cells in large prostate cancer tissue sections.

Our aim right from the beginning was to develop an open-source method that is both highly robust and flexible enough to be widely adapted and utilized by researchers all over the world. Our platform has already been used in seven publications and is currently used in several others studies so it seems that we have succeeded.

This makes me very happy, since it has always been important for me to be able to solve problems and make things work – I guess it tickles the little engineer inside me!

- Sami Blom

In the two other publications of the thesis, Sami utilised the multiplex methodology on clinical samples for advancing prostate cancer research.

First, he was the second author in a study showing that a protein called caveolin-1 switches the effects of TGF-beta in prostate cancer cells from tumor-suppressive to tumor-promoting and that the same features were present in clinical prostate cancer. Next, he focused on the usually neglected part of the prostate cancer tissue samples, the stroma, and showed that the proportion of fibroblasts present in stroma is an independent predictive factor for patient outcome.

These data suggest that stromal features could improve prognostic assessment of prostate cancer. It would be highly interesting to measure fibroblasts in the diagnostic needle biopsies of low-grade prostate cancer in order to study if stromal features can predict outcome in samples typically obtained in the very early phase of prostate cancer.

During the last year, Sami has worked especially hard to get the thesis finished while starting a completely different career phase. He currently works as an application manager at Aiforia Technologies, originally a FIMM spin-off company, where his responsibility is to manage a team that is teaching artificial intelligence to perform image analysis in various applications.

Sami wants to thank his supervisors, the group members, and all his collaborators for all the support throughout the thesis project. He thinks that FIMM and the Meilahti Campus provide world-class facilities to conduct multidisciplinary biomedical and medical research.

The public examination of Sami Blom’s doctoral dissertation will take place on 27 September at 12 o'clock noon in Lecture Hall 1 at Haartman Institute, Haartmaninkatu 3 with the permission of the Faculty of Medicine of the University of Helsinki. The thesis has been supervised by Dr. Teijo Pellinen and Professor Olli Kallioniemi. Professor Patrick Micke (Uppsala University, Sweden) will serve as the opponent and Professor Johanna Arola as the custos. The dissertation is also available in an electronic form.