Development of a Fully Automated Method to Obtain Reproducible Lymphocyte Counts in Patients With Colorectal Cancer

Development of a digital algorithm for assessing tumor-stroma ratio, tumor budding and tumor infiltrating lymphocytes in vulvar squamous cell carcinomas

Tumor-stroma ratio (TSR), tumor budding (TB), and tumor-infiltrating lymphocytes (TILs) are prognostic markers in some cancers but with unknown significance in vulvar squamous cell carcinoma (VSCC). This pilot study primarily aimed to develop a digital method for evaluating TSR, TB and TILs in VSCC and secondarily to investigate variation in these factors by p16 status. An independent training set stained with CD3/cytokeratin and CD8/cytokeratin was used to develop a deep learning-based Application Protocol Package (APP) segmenting tissue into background, epithelium, or stroma. TSR was defined as percentage of tumor epithelium relative to total tumor area, and tumor buds were defined as clusters of 1-4 tumor cells. A second APP quantified CD3+ and CD8+ lymphocytes in the intraepithelial and stromal compartments, respectively. The digital algorithms were applied to the study cohort of 41 VSCC cases, achieving satisfactory performance without manual corrections. TSR ranged between 33 and 91% with median of 64%, and median number of buds was 4 (range: 0-48) buds/mm2. Median density and range of CD3+ lymphocytes were 222 (13-2320) cells/mm2 in the intraepithelial and 1978 (397-6683) cells/mm2 in the stromal compartment, respectively. CD8+ lymphocyte counts were lower. There was a tendency towards lower TSR and higher number of buds in p16-negative compared with p16-positive VSCC. Finally, automated measures were compared with manual evaluations showing high concordance. The developed automated method provided precise and objective measurements of TSR, TB and TILs. The algorithms should be validated in a larger cohort and correlated with clinicopathological characteristics and prognosis to determine their clinical relevance.

Number of intraepithelial lymphocytes and presence of a subepithelial band in normal colonic mucosa differs according to stainings and evaluation method

Chronic watery diarrhea is a frequent symptom. In approximately 10% of the patients, a diagnosis of microscopic colitis (MC) is established. The diagnosis relies on specific, but sometimes subtle, histopathological findings. As the histology of normal intestinal mucosa vary, discriminating subtle features of MC from normal tissue can be challenging and therefore auxiliary stainings are increasingly used. The aim of this study was to determine the variance in number of intraepithelial lymphocytes (IELs) and presence of a subepithelial band in normal ileum and colonic mucosa, according to different stains and digital assessment. Sixty-one patients without diarrhea referred to screening colonoscopy due to a positive feacal blood test and presenting with endoscopically normal mucosa were included. Basic histological features, number of IELs, and thickness of a subepithelial band was manually evaluated and a deep learning-based algorithm was developed to digitally determine the number of IELs in each of the two compartments; surface epithelium and cryptal epithelium, and the density of lymphocytes in the lamina propria compartment. The number of IELs was significantly higher on CD3-stained slides compared with slides stained with Hematoxylin-and-Eosin (HE) (p<0.001), and even higher numbers were reached using digital analysis. No significant difference between right and left colon in IELs or density of CD3-positive lymphocytes in lamina propria was found. No subepithelial band was present in HE-stained slides while a thin band was visualized on special stains. Conclusively, in this cohort of prospectively collected ileum and colonic biopsies from asymptomatic patients, the range of IELs and detection of a subepithelial collagenous band varied depending on the stain and method used for assessment. As assessment of biopsies from patients with diarrhea constitute a considerable workload in the pathology departments digital image analysis is highly desired. Knowledge provided by the present study highlight important differences that should be considered before introducing this method in the clinic.

Neoadjuvant intratumoral influenza vaccine treatment in patients with proficient mismatch repair colorectal cancer leads to increased tumor infiltration of CD8+ T cells and upregulation of PD-L1: a phase 1/2 clinical trial

BACKGROUND

In colorectal cancer, the effects of immune checkpoint inhibitors are mostly limited to patients with deficient mismatch repair tumors, characterized by a high grade infiltration of CD8+T cells. Interventions aimed at increasing intratumoral CD8+T-cell infiltration in proficient mismatch repair tumors are lacking.

METHODS

We conducted a proof of concept phase 1/2 clinical trial, where patients with non-metastasizing sigmoid or rectal cancer, scheduled for curative intended surgery, were treated with an endoscopic intratumorally administered neoadjuvant influenza vaccine. Blood and tumor samples were collected before the injection and at the time of surgery. The primary outcome was safety of the intervention. Evaluation of pathological tumor regression grade, immunohistochemistry, flow cytometry of blood, tissue bulk transcriptional analyses, and spatial protein profiling of tumor regions were all secondary outcomes.

RESULTS

A total of 10 patients were included in the trial. Median patient age was 70 years (range 54-78), with 30% women. All patients had proficient mismatch repair Union of International Cancer Control stage I-III tumors. No endoscopic safety events occurred, with all patients undergoing curative surgery as scheduled (median 9 days after intervention). Increased CD8+T-cell tumor infiltration was evident after vaccination (median 73 vs 315 cells/mm², p<0.05), along with significant downregulation of messenger RNA gene expression related to neutrophils and upregulation of transcripts encoding cytotoxic functions. Spatial protein analysis showed significant local upregulation of programmed death-ligand 1 (PD-L1) (adjusted p value<0.05) and downregulation of FOXP3 (adjusted p value<0.05).

CONCLUSIONS

Neoadjuvant intratumoral influenza vaccine treatment in this cohort was demonstrated to be safe and feasible, and to induce CD8+T-cell infiltration and upregulation of PD-L1 proficient mismatch repair sigmoid and rectal tumors. Definitive conclusions regarding safety and efficacy can only be made in larger cohorts.

TRIAL REGISTRATION NUMBER

NCT04591379.