The new wave in laboratory medicine

A pathologist’s perspective


Prof. Tan Puay Hoon, Chairman, Division of Pathology and Senior Consultant, Department of Anatomical Pathology at Singapore General Hospital (SGH) enjoys the rare distinction of being the first woman from Singapore to be a volume editor of the World Health Organisation’s Classification of Tumours of the Breast. A key figure in Singapore’s anatomical pathology scene, Prof. Tan shares her views with Dia:gram on what makes pathology the foundation of medicine and the forces shaping its future.


Prof. Tan Puay Hoon has many firsts to her credit. Among them, is being appointed the first Chairman of the Division of Pathology at one of Singapore’s leading hospitals. The role was created following the formation of this Division in 2016 to oversee four departments – Anatomical Pathology, Clinical Pathology, Molecular Pathology and Microbiology.

“Prior to this, Pathology was one large department with many laboratories that functioned separately even though there were synergies among them. We realised we could tap on the collective experience and expertise that rest within our teams by consolidating laboratories with complementary services into Departments, to ultimately strengthen pathology subspecialty support for patient care. The Division of Pathology interfaces with existing and new Divisions in SGH, allowing seamless interaction with medical and surgical disciplines as well as the SingHealth Duke-NUS Disease Centres,” said Prof. Tan.

The Division has over 500 employees comprising laboratory professionals, technical staff and clinicians, making it the largest of its kind in Singapore.

“Our endeavour now is to build a forward-looking and innovative pathology service that keeps pace with the latest developments, and better still, leads the way in formulating novel pathology tools and technologies,” she added.

This, Prof. Tan said, is largely because the field has evolved tremendously. Gone are the days when pathologists were occupied primarily with the diagnosis, classification, and subclassification of disease. Today, pathologists play a crucial role by providing prognostic and predictive information that helps the physician in rendering appropriate treatment.

The evolving role of the pathologist


“I have always been fascinated by pathology. I liked the systemic manner of identifying disease patterns and coming to a pathological diagnosis. Looking down at the slides through a microscope made me appreciate the beauty of this discipline even more. It was, and still remains, such a knowledge-rich subject that has both breadth and depth, spanning causation of disease to clinical manifestations that lead to appropriate diagnosis and therapy. It truly is the foundation of medicine, underpinning all medical practice,” Prof. Tan said.

High magnification view down the microscope, of an invasive breast cancer that shows crowded malignant cells with enlarged nuclei and many mitoses.

As healthcare evolves so does the role of pathologists. “Cancer diagnosis, for instance, cannot be made without pathological confirmation. Pathologists prognosticate disease which determines how long patients will survive, and predict the response of patients to various therapies based on assessment of the tumour and its biological features. This makes them an integral part of the cancer management team,” she added.

“But more needs to be done to raise the profile of pathology as a specialty, giving it the recognition it deserves,” cautioned Prof. Tan. “In the absence of direct patient contact, it tends to play a supporting rather than starring role in medicine.” On this point, Prof. Tan also said pathologists need to step up and take charge rather than continue the status quo.

Prof. Tan believes there needs to be a greater appreciation for the role of pathology in medicine, in order to sustain the future talent pipeline. Sometimes perspective from the next generation helps. A mother-of-four, Prof. Tan remembers a conversation with her daughter who was a medical student then, and is now an internal medicine resident. She said to me: “Many of us think all you (pathologists) do is research.’ It made me realise that it is up to those of us in senior positions to showcase its value so that we can encourage our best and brightest to join.”


Keeping pace with changes in healthcare


Advancements since the 1970s, as seen with automation, computerisation, and immunoassay and molecular techniques, have transformed the practice of laboratory medicine. Which is why Prof. Tan advocates keeping up with developments in medicine, “Otherwise one gets readily left behind by the rapid advances in disease classification, prognostic and therapeutic developments.”

“We need to continuously upskill ourselves and embrace technologies that can help us to make a positive impact. Automation in pathology continues to be at the fore, with improved technologies reducing the requirement for labour intensive processes, promoting standardisation and consistency in laboratory testing, and alleviating manpower constraints,” she added.

When asked whether the pathologist’s role could become irrelevant in the time to come, she said: “Molecular tools are revolutionising how we diagnose and treat diseases. With new therapies emerging and the growing shift towards individualised treatment, we are now facing a molecular information explosion which requires a pathologist to carefully curate and interpret the data.”

Speaking about the exciting developments in diagnostics, Prof. Tan said, “Point of care testing, which may in the future provide an extensive laboratory menu for patients within the community itself, could very well be the norm moving forward – bringing pathology services right to the patient’s doorstep.

Digital pathology, artificial intelligence and deep learning are other areas that will equip pathologists with tools that will redefine healthcare.”

Prof. Tan was the first to introduce digital pathology at Singapore General Hospital. Her department at the hospital was also one of the first in the world to look at digital pathology in a routine laboratory setting.

From research to best practice


She is equally passionate about her work in breast cancer. “My interest in breast pathology began as a trainee and then Senior Registrar during the Singapore Breast Screening Pilot Project. It was wonderful to see a program being piloted for early detection of breast cancer among women in Singapore. The results of this pilot program led to the launch of the National Breast Screening Program, BreastScreen Singapore in 2002.” Prof. Tan has continued to be a part of this initiative since inception.


Through that experience she recalls, “I began to study early breast cancer diagnosed through screening and gather local data on the disease. When I embarked on a Doctor of Medicine thesis I focused on breast ductal carcinoma in situ (DCIS). Our research group continues to work on breast DCIS to this day.” Prof. Tan has authored more than 400 publications. Her latest book titled Atlas of Differential Diagnosis in Breast Pathology, which was five years in the making, was recently published.

Prof. Tan was also part of a multidisciplinary team of scientists that discovered MED12, a gene that is responsible for the formation of fibroadenomas, the most common benign breast tumour in women. It is estimated that millions of women around the world are diagnosed with fibroadenoma annually. The group’s breakthrough research went on to be published in the seminal scientific journal, Nature Genetics.

Not one to rest on her laurels, Prof. Tan continues to pursue breast pathology research. She is currently studying triple negative breast cancer, a type of breast cancer that does not express estrogen, progesterone or HER2 receptors. This means therapeutic options for such patients are often limited as there are no targets for treatment. She is also currently looking at breast fibroepithelial lesions and the translational application of the team’s research discoveries to diagnostics. In conjunction with this research, Prof. Tan hopes to seek approval for establishing a data registry that tracks consented patients with fibroepithelial lesions, so that more information can be gleaned to help improve clinical management.

She is also active as a member of several renowned associations, often collaborating with pathologists to share best practices and exchange ideas. One area that Prof. Tan keenly supports is capacity building efforts in the Association of Southeast Asian Nations (ASEAN) region where pathologists often have limited access to technology or tools. Prof. Tan, together with her colleague Dr. Angela Chong, helms the annual SGH Breast Pathology Course which, now in its 9th year, brings together experts from the region and around the world.

Preparing for the future


The changing economics of healthcare provision calls for new ways of working. Yet, the opportunities in pathology have perhaps never been greater – with more focus on care collaboration, the adoption of newer advances in testing technologies, and the shift towards personalised medicine.

For those considering pathology as a career option, Prof. Tan has this advice, “Pathology is a great career option for individuals who love the challenge of being immersed in a discipline where the investigative mind unravels myriad information points to reach precise diagnoses and beyond.”

          Other Issues

          › Edition 2017 Vol 2

          › Edition 2017 Vol 1