The most frequent cancer types are lung and breast cancer in the Western world. However, the prognosis of breast cancer patients shows an improved tendency, while lung cancer types remained with high mortality. Intratumor heterogeneity (ITH) frequently leads to the failure of treatments, so there is an unmet need revealing ITH at single cell resolution. Our aim was to study female-derived human H1975 lung and MDA-MB-231 triple-negative breast cancer adenocarcinoma cell line models using single cell mass cytometry. Nine of thirteen carcinoma markers showed significant differences in the percentage of cells. Our current work shed light on the intra- and inter cell line heterogeneity still preserved in the studied, widely-used adenocarcinoma laboratory models.