Low PD-L1 expression in immune cells predicts the presence of nodal metastasis in early invasive (pT1) colorectal cancer: a novel tool to tailor surgical treatment.

AIMS: The current criteria for surgical treatment after endoscopic resection of a pT1 colorectal carcinoma (CRC) are unsatisfactory because nodal involvement is rarely present. This study investigates the correlation between PD-L1 expression and nodal metastasis in pT1 CRCs to enable its use for tailoring surgical treatment after endoscopic removal. METHODS AND RESULTS: Histopathological features of 81 surgically resected pT1 CRC, 19 metastatic and 62 non-metastatic cases were assessed. PD-L1 expression was evaluated by immunohistochemistry (clone 22C3) and independently assessed by two pathologists using tumour proportion score (TPS), combined positive score (CPS) and immune cell score (ICS). The correlation between PD-L1 expression and nodal metastasis, the optimal cut-off values, interobserver agreement and impact upon patients' surgical management were determined. PD-L1 expression in terms of CPS and ICS independently correlated with lymph node metastasis (PD-L1CPS : OR = -2.5, 95% CI = -4.11 to -0.97, P = 0.008 and PD-L1ICS : OR = -1.85, 95% CI = -2.90 to -0.79, P = 0.004) and < 1.2 CPS and <1.3% ICS were identified as the optimal cut-off values to discriminate between metastatic and non-metastatic patients. In our cohort, the implementation of these cut-off values would have avoided a significant rate of unnecessary surgeries in pN0 patients (PD-L1CPS = 43.2; PD-L1ICS = 51.9%). Ultimately, PD-L1 evaluation showed good interpathologist concordance in absolute terms [PD-L1CPS interclass correlation coefficient (ICC) = 0.91; PD-L1ICS ICC = 0.793] and using the identified cut-off values (PD-L1CPS ICC = 0.848; PD-L1ICS ICC = 0.756). CONCLUSIONS: Our study shows that PD-L1 expression is an effective predictor of nodal status and could improve patient selection for surgery after endoscopic removal of pT1 CRCs.

Where Morphological and Molecular Classifications Meet: The Role of p53 Immunohistochemistry in the Prognosis of Low-Risk Endometrial Carcinoma (GLAMOUR Study).

No prospective study has validated molecular classification to guide adjuvant treatment in endometrial cancer (EC), and not even retrospective data are present for patients with morphological low-risk EC. We conducted a retrospective, multicenter, observational study including 370 patients with low-risk endometrioid EC to evaluate the incidence and prognostic role of p53 abnormal expression (p53abn) in this specific subgroup. Among 370 patients, 18 had abnormal expressions of p53 (4.9%). In 13 out of 370 patients (3.6%), recurrences were observed and two were p53abn. When adjusting for median follow-up time, the odds ratio (OR) for recurrence among those with p53abn versus p53 wild type (p53wt) was 5.23-CI 95% 0.98-27.95, p = 0.053. The most common site of recurrence was the vaginal cuff (46.2%). One recurrence occurred within the first year of follow-up, and the patient exhibited p53abn. Both 1-year and 2-year DFS rates were 94.4% and 100% in the p53abn and p53wt groups, respectively. One patient died from the disease and comprised p53wt. No difference in OS was registered between the two groups; the median OS was 21.9 months (16.4-30.1). Larger multicenter studies are needed to tailor the treatment of low-risk EC patients with p53abn. Performing molecular classification on all EC patients might be cost-effective, and despite the limits of our relatively small sample, p53abn patients seem to be at greater risk of recurrence, especially locally and after two years since diagnosis.