There is a whole micro-world in every human body organ where various processes are happening and contributing to proper functioning.
In the last blog post, I described how computers could provide reliable cancer diagnostics by eliminating abnormalities from WSI. However, it is vital to understand cancer biology before developing models to mimic pathologists. Many factors are well known for causing cancers. These factors are known as hallmarks and can be separated into emerging and developed hallmarks. The evolution of tumors happens progressively by a multistep pathogenesis process that revolves around the cell.
A cell is a small entity in the human body that can perform all necessary processes for sustaining life. These cells are present in all organs and carry out different functions such as transportation of oxygen, locomotion, excretion of materials, and other stuff. A cell comprises cytoplasm (an amalgam of protein and amino acids) and a Nucleus (which contains DNA and RNA). These cells have a certain lifespan; after that, they die and must be replaced. The cell cycle causes cells to break and produce new cells. However, this replication process makes errors in the new copy of DNA, knowns as mutations. Our body has a natural control mechanism that corrects these errors and stops further division in case of significant abnormality. It takes years to develop such mutations that escape the control mechanism and makes them grow indefinitely. Cancer emerges because of the failure of these controlling mechanisms.
An illustration of tumor microenvironment where different cellular signals may contribute to the evolution of cancer. (Picture Courtesy: Wikipedia)
The growth of cancer is affected by the microenvironment that consists of immune cells, vessels, signaling molecules, other proteins. Figure 1 shows various elements in the tumor microenvironment. Blood vessels provide oxygen and nutrients to normal and cancerous cells similarly. Cancerous cells try to invade normal cells. Immune cells try to stop and suppress tumor cells, and regulatory cells stop immune cells. As a result of this heterogenous functionality of elements in this microenvironment, a tumor can either be eliminated or escaped from this control. The presence of cancer is further quantified by grade, which determines how well-differentiated it is and how aggressively it can grow.
On the other hand, the cancer stage explains how big the tumor is and how far it has spread into the organ. Pathologists follow instructions from the WHO bluebook to relate tissues to approved histological standards. These books provide approved guidelines and steps to relate cancer to specific parameters. They are updated based on new developments every few years. The pathologist’s decision may have subjective variation and may require consultation with another expert pathologist in some cases.
The secondment gave insight into cancer basics, pathological analysis of various cancer types, and multiple biomarkers for diagnosis and prognosis. SUH organized several sessions to visualize cellular features in bladder, breast, and skin tissue slides. ESR was briefed about treatments that are carried out based on the clinical nature of the disease. Common medications against cancer are; 1) Immunotherapy that boosts the immune cell response against cancer. 2) Chemotherapy after removing the tumor area that kills all dividing cells. 3) Phototherapy uses high-power radiation to kill cancerous cells. 4) Hormone therapy blocks or removes hormones that fuel cancer growth.
Thanks to Prof. Emiel Janssen for providing opportunities to interact and learn from individuals on the clinical side.
Looking into histological glass slides at Pathology Department at SUH with Prof. Janssen, ESR 11 (Umay Kiraz) and ESR2 (Yuandou Wang)
I will keep you posted further on the published outcome from my project in the next blog post. Stay tuned till then!
Neel Kanwal – ESR4