Affordable panel of techniques for prediction of molecular classification of a series of medulloblastomas in a reference pediatric hospital in Colombia

Molecular classification of medulloblastomas helps in improving risk-stratification. However, application in routine practice remains a challenge in low and middle-income countries. In Colombia, children often have delayed and uncomplete diagnosis. We underwent a retrospective analysis of 49 cases of medulloblastoma treated between 2009 and 2017 in a reference pediatric hospital in Bogotá, Colombia. This manuscript reports the use of a immunohistochemical plus PCR panel to distinguish SHH, WNT, and non-SHH/WNT tumors and details their clinical and pathological features. We analyzed Beta-catenin, p75NTR, PIGU, OTX2, YAP1 and P53 by immunohistochemistry and performed PCR for C-myc and N-myc amplification. We found a high percentage of SHH tumors and a high prevalence of desmoplastic-nodular tumors in our series. The male: female ratio was different from reported in other latitudes. We believed it would be important to complement these results by new generation sequencing and the gold standard in the medulloblastoma diagnosis, the methylation analysis. However, the panel we propose is useful to predict the molecular group. This is the first medulloblastoma case series in Colombia.