Introduction:
Colorectal cancer (CRC), one of the most common cancers, is a major public health issue globally, especially in Western countries. In Poland, both in men and women, CRC is a cancer with a high incidence and occupies the 2nd–3rd position among morbidity and deaths. Because of milestones in molecular analysis and deeper insight into molecular pathways, personalised treatment is now possible. Next-generation sequencing (NGS) technology enables panel detection of many genes and therefore identification of people with cancer-predisposing mutations.

Aim of the research:
In the current study we analysed molecular studies of colorectal cancer in patients ≤ 50 years of age.

Material and methods:
We qualified patients without prior radio- and chemotherapy into the inclusion criteria. We isolated DNA from FFPE. We used the Illumina Hot-Spot Cancer Panel containing 50 genes (700 amplicons).

Results:
The median of age was 43 years. The female : male ratio was 1 : 1. We recorded the following mutation frequencies: TP53 76%, APC 57%, KRAS 43%, NRAS 29%, SMAD4 9%, PIK3CA 14%, and FBXW7 5%. We noted the co-occurrence APC/KRAS/TP53 mutation in 20% of patients.

Conclusions:
Co-occurrence of mutations was found in 86% of patients, most often 2 or 3. IDH1 was found only in patients with a better prognosis, while the TP53, APC, and KRAS mutations occurred significantly more often in patients with a worse prognosis.