Clinical outcomes of muscle invasive bladder Cancer according to the BASQ classification

We evaluated the clinical efficacy and prognosis of muscle-invasive bladder cancer according to the basal/squamous-like (BASQ) classification system based on immunohistochemical staining [CK5/6(+), CK14(+), GATA3(-), and FOXA1(-)].

One hundred patients diagnosed with muscle-invasive bladder cancer (cT2-4 N0-3 M0) were included in the study. All patients underwent radical cystectomy after transurethral removal of bladder tumor. Immunostaining was performed for CK5/6, CK14, FOXA1, and GATA3 antibodies on tissue microarray slides, and expression patterns were quantitatively analyzed using a scanning program.

The median follow-up time was 77.4 (interquartile range: 39-120.9) months. The mean age of the patients was 65.1 ± 11.2 years. FOXA1 or CK14 expression greater than 1% was respectively positively and negatively correlated with overall survival (OS; p = 0.011 and p = 0.042, respectively), cancer-specific survival (CSS; p = 0.050 for both), and recurrence-free survival (RFS; p = 0.018 and p = 0.040, respectively). For CK5/6+ and GATA3- or FOXA1- expression, 10% CK5/6+ cells were negatively correlated with OS (p = 0.032 and p = 0.039, respectively) and with RFS in combination with FOXA1- only (p = 0.050).

In this study, CK14 expression was associated with a poor prognosis. The new classification system of bladder cancer based on molecular characteristics is expected to helpful tool for the establishment of personalized treatment strategies and associated prediction of therapeutic responses.