Canine urothelial carcinoma (UC) and prostatic carcinoma (PC) often present diagnostic challenges due to their anatomical locations. The BRAF V595E mutation, analogous to the human BRAF V600E mutation, has been identified in UC and PC. Digital PCR of urine is a non-invasive diagnostic method of mutation detection, but the availability of the necessary equipment is limited. This study aimed to develop a conventional PCR to detect the BRAF V595E mutation in urine and prostatic wash specimens from dogs with UC or PC. Specific primers for detecting wild-type and mutant BRAF V595E genes were validated in 34 formalin-fixed paraffin-embedded (FFPE) tissues, 116 urine samples, and 9 prostatic wash specimens. The results showed that the BRAF V595E mutation detection rate for UC and PC in the tissues was 51.6%. The detection rate in liquid specimens from dogs with lower urinary tract or prostate masses was 53.2%. Of the 41 cases with follow-up, 16 were further diagnosed with UC or PC, with 75% of liquid specimens from these dogs showing the BRAF V595E mutation. This conventional PCR method provides a reliable and non-invasive screening tool for UC and PC in dogs, especially in settings without advanced equipment.

YKL-40, a secretory glycoprotein, is known as a prognostic biomarker in human cancers, but its role in canine multicentric lymphoma is not well understood. This study aimed to investigate serum YKL-40 levels in thirty dogs with multicentric lymphoma to determine their prognostic value, association with patient characteristics, and potential to predict chemotherapy response. Serum samples were collected before, during, and after chemotherapy, and YKL-40 level was measured using ELISA. The results showed that the pretreatment serum YKL-40 levels were significantly higher in dogs with multicentric lymphoma (394.0 pg/mL, n = 30) than in healthy controls (218.6 pg/mL, n = 11) (p = 0.012). While a cutoff value of 445.1 pg/mL was observed, further studies are needed to clarify its diagnostic utility. Dogs with clinical stage V had the highest YKL-40 levels (p = 0.027), potentially reflecting disease severity. Furthermore, YKL-40 levels decreased after chemotherapy (p = 0.030). However, YKL-40 levels showed no significant association with progression-free survival (PFS) (HR = 0.93, p = 0.830) or overall survival (OS) (HR = 0.99, p = 0.267). In conclusion, serum YKL-40 levels may potentially detect the disease severity, but its prognostic role remains uncertain. Further studies are required to evaluate serum YKL-40 levels as a potential indicator of treatment response or disease recurrence.