A Simple Staining Test Predicts Early Return of Colorectal Cancer After Liver Surgery

For patients whose colorectal cancer has spread to the liver, surgery offers the best chance of a cure, but the disease has an unsettling habit of coming back. Now a study from Cho Ray Hospital in Vietnam suggests that a routine laboratory stain, already available in most pathology departments, may identify which of these patients face the highest risk of early recurrence. The research, published in Cancer Reports, found that an abnormal pattern of p53 protein staining in liver metastases predicted tumor return far more reliably than many traditional clinical measures, and it did so in a group of patients who are often the hardest to counsel: those whose tumors did not fully melt away after chemotherapy.

The biology behind the test centers on p53, the protein product of the TP53 gene, often described as the guardian of the genome. In healthy cells, p53 acts as a molecular checkpoint, halting the cell cycle when DNA is damaged, coordinating repair, and triggering apoptosis, or programmed cell death, when the damage is beyond repair. TP53 is among the most frequently mutated genes in colorectal cancer, and when it fails, cells can proliferate unchecked, resist chemotherapy, and acquire invasive properties. Because mutated p53 protein is often unusually stable or entirely absent, immunohistochemistry, a staining technique that uses antibodies to reveal protein location in tissue sections, can serve as a proxy for the underlying mutation. The catch has been interpretation: older studies used arbitrary thresholds, such as staining in just 10 percent of tumor cells, which later proved poor predictors of actual TP53 mutation status.

The Vietnamese team adopted a newer, pattern-based classification originally developed by Köbel and colleagues in ovarian carcinoma. Under this scheme, aberrant p53 expression means either strong, diffuse nuclear staining in at least 80 percent of tumor cells, consistent with a stabilized mutant protein, or a complete absence of staining, consistent with a truncated nonfunctional protein. Everything in between is classified as a wild-type pattern. This approach has shown high concordance with molecular sequencing in prior work, and the researchers wanted to know whether it could carry prognostic weight in a specific and vulnerable population: patients with colorectal liver metastases who received neoadjuvant chemotherapy but did not achieve a pathological complete response.

That population matters because complete pathological response, meaning no viable cancer cells left in the resected metastatic tissue, occurs in only about 4 to 6 percent of these patients. Those who do achieve it enjoy markedly better survival and lower recurrence rates. The vast majority who do not face a substantially worse prognosis, yet dedicated studies of biomarkers in this subgroup have been scarce. Between January 2022 and June 2023, the team enrolled 92 consecutive patients with colorectal liver metastases, all treated with FOLFOXIRI, an intensive intravenous chemotherapy combination given every two weeks. A multidisciplinary tumor board assessed responses every eight to nine weeks against standardized surgical criteria. Fifty-four patients proved eligible for resection of both the primary tumor and the liver metastases, and after excluding four cases with inadequate tissue blocks, ten who achieved pathological complete response, and one found unresectable during surgery, 39 patients with residual viable tumor formed the final cohort.

The results were striking in their symmetry: 19 patients showed wild-type p53 staining and 20 showed the aberrant pattern, a near-even split that mirrors the roughly 65 percent positivity reported in some earlier metastasis studies. During follow-up, 35 of the 39 patients experienced recurrence, and the median recurrence-free survival for the whole cohort was 9.4 months. When the researchers stratified outcomes by staining pattern, the curves separated early and decisively. By six months after surgery, the estimated recurrence probability was 46.4 percent in the aberrant group compared with 21.4 percent in the wild-type group. Recurrence in the aberrant group climbed so quickly that it reached 100 percent by 14 months, while the wild-type group, though still faring poorly, had not yet reached that grim ceiling by month 19.

Statistical modeling confirmed that the staining pattern was not merely a correlate of other risk factors. In univariate Cox analysis, several features predicted recurrence, including a total metastatic tumor burden greater than six centimeters, which carried the highest hazard ratio at 5.62, more than four liver lesions, a positive resection margin, and receiving fewer than the full 12 cycles of preoperative chemotherapy. But when the investigators built a parsimonious multivariate model, constrained to four variables to avoid overfitting given the modest sample size, aberrant p53 expression remained an independent prognostic factor, associated with a 3.78-fold increase in recurrence risk compared with wild-type expression. Total tumor size above six centimeters also retained significance with a hazard ratio of 5.23. The number of metastases and the completeness of chemotherapy cycles, by contrast, lost their statistical weight once other factors were accounted for.

The molecular logic connecting mutant p53 to early recurrence is plausible and multifaceted. Loss of p53 function can upregulate matrix metalloproteinases, enzymes that remodel tissue and facilitate tumor invasion. It can promote epithelial-mesenchymal transition, the cellular program that endows cancer cells with migratory and invasive capacity. It can reshape the tumor microenvironment, encouraging angiogenesis and blunting antitumor immune responses. Perhaps most relevant to this chemotherapy-treated cohort, many first-line colorectal cancer drugs, including oxaliplatin and irinotecan, work by inflicting DNA damage and activating p53-dependent apoptotic pathways. When p53 is dysfunctional, that lethal response is blunted, allowing resistant micrometastatic clones to survive treatment and seed early relapse. This mechanism aligns with findings from a German study by Pilat and colleagues, which showed that TP53 mutation predicted poor outcomes specifically in patients who received neoadjuvant chemotherapy, not in those who did not.

The clinical implications are pragmatic. p53 immunohistochemistry is inexpensive, technically simple, and already embedded in routine pathology workflows, unlike next-generation sequencing, which remains costly and unevenly distributed. Notably, a recent study by Kim and colleagues using the same pattern-based criteria found that aberrant p53 staining actually outperformed sequencing-derived TP53 mutation status in prognostic accuracy for overall survival, with a hazard ratio of 4.352 versus a nonsignificant 1.739 for mutations. For the non-pCR patients in the Vietnamese cohort, an aberrant staining result could justify intensified surveillance with imaging and carcinoembryonic antigen testing, and potentially inform decisions about more aggressive adjuvant therapy, though the authors caution that such strategies require validation in prospective trials.

The study also has honest boundaries. With 39 patients and 35 recurrence events, the investigators deliberately limited their multivariate model to four covariates, which meant that RAS and BRAF mutations, available for 38 patients through pyrosequencing, could only be explored descriptively. An exploratory analysis of concurrent aberrant p53 and RAS/BRAF alterations, restricted to just seven patients, showed no significant association with recurrence, a result the authors attribute to inadequate statistical power rather than evidence of no effect. An analysis of overall survival was similarly underpowered, with only seven deaths, so recurrence-free survival remained the more informative endpoint. The team also relied on staining rather than molecular testing to infer TP53 status, leaving room for occasional misclassification, and the single-center Asian cohort calls for external validation in diverse populations.

Even with those caveats, the findings sharpen a picture that has long been muddled by inconsistent methodology. Earlier studies of p53 in colorectal liver metastases reached contradictory conclusions, but much of the confusion now appears attributable to outdated staining thresholds that poorly reflected biology. By applying a validated pattern-based interpretation to a well-defined, uniformly treated cohort, this study suggests that the humble p53 stain, when read correctly, can do real prognostic work in one of oncology’s most challenging scenarios: telling patients with residual disease after chemotherapy just how aggressively their cancer is likely to return, and giving clinicians a molecularly grounded basis for watching them more closely.

Subject of Research: Prognostic value of pattern-based p53 immunohistochemistry in colorectal liver metastases without pathological complete response after neoadjuvant chemotherapy

Article Title: Pattern‐Based P53 Immunohistochemistry Predicts Recurrence in Colorectal Liver Metastases Without Complete Pathologic Response After Neoadjuvant Chemotherapy

Article References: Ho, P. T. H., Nguyen, D. D., Hao, V. D. T., Tran, G. H., Trung, L. V., Van Hoang, T., & Nguyen, H. B. (2026). Pattern‐Based P53 Immunohistochemistry Predicts Recurrence in Colorectal Liver Metastases Without Complete Pathologic Response After Neoadjuvant Chemotherapy. Cancer Reports, 9(10), Article e70701. https://doi.org/10.1002/cnr2.70701

Image Credits: AI Generated

DOI: 10.1002/cnr2.70701

Keywords: colorectal cancer, liver metastases, p53, TP53, immunohistochemistry, neoadjuvant chemotherapy, FOLFOXIRI, recurrence-free survival, pathological complete response, biomarker, prognosis, hepatic resection