Vietnamese researchers have identified important differences in breast cancer biomarker testing across hospitals. The findings reveal why laboratory standardisation, specialist expertise and quality assurance are increasingly important to cancer diagnostics in Vietnam.
The Same Tumour Can Produce Different Laboratory Results
Not every diagnostic challenge in cancer care involves detecting a tumour.
Sometimes, the more difficult challenge is ensuring that different pathology laboratories interpret the same tumour consistently.
This distinction matters because modern cancer treatment increasingly depends on molecular and biological characteristics identified through laboratory testing.
For breast cancer patients, several biomarkers help physicians understand tumour behaviour and determine appropriate treatment strategies.
These include estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67.
But how consistently are these biomarkers measured across different hospitals?
A Vietnamese study published in 2025 provides an important perspective.
Researchers examined immunohistochemistry (IHC) testing across 10 hospitals in Vietnam, including institutions in Ho Chi Minh City, Hanoi, Đà Nẵng, Huế, Cần Thơ and Cà Mau.
Their findings revealed substantial differences in reproducibility between biomarkers.
ER testing demonstrated relatively strong consistency, with a coefficient of variation of just 4.8%.
Ki-67, however, showed considerably greater variability, with a coefficient of variation of 17% at the 30% classification threshold.
The results highlight a fundamental issue facing pathology laboratories: offering the same diagnostic test does not necessarily mean producing equally consistent results.
What Did the Vietnamese Pathology Study Find?
The research, titled Reproducibility of Immunohistochemical Testing of Estrogen Receptors, Progesterone Receptors, Human Epidermal Growth Factor Receptor-2 (HER2) and Ki-67 in Vietnam, was published in the British Journal of Biomedical Science.
It was designed as an external quality assessment study.
Participating hospitals prepared breast cancer tissue samples, which were then circulated for testing and interpretation across the participating laboratories.
The objective was to determine how consistently different laboratories could evaluate the same biomarkers.
The results demonstrated varying levels of agreement.
| Biomarker | Key finding | Interpretation |
|---|---|---|
| ER | 4.8% CV; 92% agreement | Strong reproducibility |
| PR | 7.1% CV; 88% agreement | Relatively strong reproducibility |
| HER2 | 9.7% CV; 77% agreement | Greater variation |
| Ki-67 | 17% CV; 84% agreement at the ≥30% threshold | Highest reported CV |
| HER2-low | Kappa 0.323; 50% agreement | Relatively weak classification agreement |
Source: 2025 Vietnamese multicentre pathology reproducibility study. CV denotes coefficient of variation. The measures are not directly interchangeable, and the Ki-67 CV depends on the threshold used.
Importantly, these figures should not be interpreted as diagnostic error rates.
A 17% coefficient of variation does not mean that 17% of patients received an incorrect diagnosis.
Rather, it describes the relative variability observed in laboratory agreement measurements.
The study also found that Ki-67 agreement reached 84% using a 30% classification threshold and 81% using a 20% threshold.
These findings suggest that meaningful reproducibility is achievable, while also demonstrating opportunities for improvement.
Why Is Ki-67 Important in Breast Cancer Diagnosis?
Ki-67 is a protein associated with cellular proliferation.
In pathology, the Ki-67 index estimates the proportion of tumour cells actively progressing through the cell cycle.
A higher index generally indicates that a greater proportion of tumour cells are proliferating.
This information can help physicians assess tumour biology and, in selected clinical circumstances, inform treatment decisions.
For example, Ki-67 may contribute to evaluating certain hormone receptor-positive breast cancers alongside tumour grade, stage, receptor status and other clinical information.
However, Ki-67 is not a standalone determinant of treatment.
Its clinical interpretation depends on the disease context, relevant guidelines and the availability of other diagnostic information.
The challenge is that Ki-67 measurement involves several technical and interpretive steps.
Pathologists must identify appropriate tumour regions, distinguish malignant cells from surrounding tissue and assess the proportion of positively stained tumour nuclei.
Differences in staining, image selection and counting methodology can influence the reported result.
Consequently, two laboratories evaluating similar material may report different Ki-67 measurements even when both follow broadly accepted procedures.
This becomes particularly important when a result falls near a clinically relevant decision threshold.
HER2-Low Testing Reveals Another Important Challenge
The Vietnamese study identified another noteworthy finding.
Agreement in HER2-low classification was relatively weak.
Researchers reported a kappa statistic of 0.323, compared with 0.794 for HER2 testing overall.
Kappa is a statistical measure of agreement that accounts for agreement expected by chance.
A lower kappa value indicates weaker reproducibility under the classification system being evaluated.
In the study, agreement among HER2-low assessments was approximately 50%.
This matters because HER2 classification has become increasingly relevant to breast cancer treatment.
Historically, HER2 testing primarily distinguished HER2-positive cancers from HER2-negative cancers.
However, the development of antibody-drug conjugates, including trastuzumab deruxtecan, has increased clinical interest in tumours expressing relatively low levels of HER2.
Distinguishing between very low levels of biomarker expression can be technically challenging.
Subtle differences in tissue staining or interpretation may influence the classification assigned to a tumour.
The study therefore highlights the importance of careful validation, consistent scoring and specialist training as precision oncology continues to evolve.
Why Installing Advanced Laboratory Equipment Is Not Enough
For healthcare investors evaluating Vietnam’s diagnostic laboratory industry, the study has implications beyond breast cancer.
It demonstrates why developing a sophisticated pathology operation involves significantly more than purchasing equipment.
Modern immunohistochemistry laboratories may use automated staining platforms, digital scanners and advanced diagnostic software.
These technologies can improve operational consistency and efficiency.
But technology alone cannot guarantee reproducible results.
Reliable pathology depends on an integrated system encompassing tissue preparation, validated staining protocols, internal quality control, external proficiency testing and qualified personnel.
Tissue fixation is particularly important.
If tissue is inadequately preserved before testing, biomarker expression may be affected before the sample reaches the staining instrument.
Likewise, variations in antibody reagents, instrument calibration, staining protocols and scoring methods can introduce inconsistencies.
Even a technically well-performed stain requires accurate interpretation.
This means the quality of a pathology service depends on the complete diagnostic workflow, rather than any single piece of equipment.
For investors, that creates an important distinction between establishing laboratory capacity and building dependable diagnostic capability.
Quality Assurance Is Becoming a Competitive Advantage
The Vietnamese findings also illustrate why laboratory quality assurance deserves greater commercial attention.
In routine laboratory testing, service providers often compete on price, turnaround time, geographical coverage and relationships with healthcare institutions.
These factors remain important in pathology.
However, specialised diagnostic services introduce another competitive dimension: the ability to produce consistent, clinically reliable results.
A laboratory with validated workflows, documented quality performance and experienced pathologists may offer greater value than a competing provider with similar equipment but less mature quality systems.
This advantage is particularly relevant when laboratories serve multiple hospitals or process samples originating from different locations.
A centralised pathology operation must manage variation in specimen collection, preservation, transportation and preparation.
Without consistent procedures, expanding the laboratory network can increase operational complexity.
Conversely, a well-managed network can standardise protocols, implement regular quality assessments and provide specialist oversight across multiple facilities.
These capabilities may support stronger relationships with hospitals, oncologists and institutional healthcare clients.
Quality assurance therefore should not be viewed simply as a regulatory or administrative expense.
It can be an important component of a laboratory group’s competitive position.
Why Specialist Pathology May Have Higher Barriers to Entry
The diagnostic laboratory industry contains different levels of technical complexity.
Routine chemistry and haematology testing can often be scaled through automation, standardised instruments and high-volume processing.
Histopathology and specialised immunohistochemistry present additional challenges.
They require skilled specimen preparation, specialised interpretation and continuing professional development.
Complex cancer cases may also require consultation among multiple pathologists.
Unlike laboratory instruments, specialist expertise cannot necessarily be acquired or expanded rapidly.
Training experienced pathologists takes years.
Developing consistent interpretation across a network requires additional investment in protocols, supervision, case review and external quality assessment.
These requirements create barriers to entry that are not purely financial.
An investor may have sufficient capital to establish a pathology laboratory.
However, replicating the operational discipline and specialist knowledge of an established provider can be considerably more difficult.
This helps explain why established diagnostic organisations may possess valuable intangible assets that are not immediately visible on their balance sheets.
These include accumulated expertise, trusted clinical relationships, validated testing systems and institutional experience.
What Does This Mean for Vietnam’s Diagnostic Laboratory Market?
Vietnam’s healthcare sector is moving toward greater use of specialised diagnostics, particularly in oncology.
As precision medicine develops, treatment decisions increasingly rely on detailed biological information rather than tumour location alone.
This creates opportunities for diagnostic providers capable of delivering reliable biomarker testing.
However, the Vietnamese reproducibility study suggests that market development should not be evaluated solely through laboratory numbers, equipment capacity or testing volumes.
The consistency of diagnostic results also matters.
For hospital groups, this may increase the value of partnerships with pathology providers demonstrating strong quality-control performance.
For independent laboratories, investment in personnel, standardisation and external proficiency testing may support differentiation.
For private equity investors considering laboratory acquisitions, quality performance deserves attention during operational due diligence.
Relevant questions include whether a laboratory participates in external quality assessment, how it documents testing reproducibility, how frequently protocols are validated and whether difficult cases receive specialist review.
A laboratory’s ability to demonstrate reliable processes may be just as important as its installed equipment or reported testing volume.
The 2025 study does not establish that any particular commercial laboratory is superior, nor does it measure financial returns from quality investment.
It does, however, provide evidence that differences in diagnostic reproducibility are measurable and operationally relevant.
Conclusion: In Pathology, Scientific Capability Is a Business Asset
The Vietnamese study offers an important lesson for healthcare providers and investors.
Diagnostic laboratories should not be evaluated exclusively by the number of tests they perform or the sophistication of their equipment.
They must also be evaluated by how consistently they produce clinically useful results.
The reported 17% coefficient of variation for Ki-67 testing and relatively weak agreement for HER2-low classification demonstrate that biomarker reproducibility remains a meaningful challenge.
At the same time, stronger agreement for other biomarkers shows that standardisation can support dependable testing.
As Vietnam’s oncology diagnostic market develops, laboratories capable of combining advanced technology with experienced specialists and rigorous quality assurance may be better positioned to build sustainable competitive advantages.
In histopathology, the barriers to entry are not only financial. They are also scientific.
And in a healthcare market increasingly shaped by precision medicine, that distinction may become commercially significant.