In the study "Expression of apoptotic and proliferative factors in the gastric mucosa of patients with systemic sclerosis" differences in proliferation, apoptosis and profibrotic factors were histologically analyzed in samples of gastric mucosa in patients with systemic sclerosis (SSc) and control group. The study included 15 patients with SSc and 5 control subjects without SSc. Patients were systematized with respect to the type and severity of systemic sclerosis. Five patients were classified into the group with limited cutaneous SSc (lcSSc) and mild disease, five with moderate diffuse, and five with severe diffuse cutaneous SSc (dcSSc). Tissue samples were immunohistochemically stained with Ki-67 antibody (proliferation), caspase-3 (apoptosis), syndecan-1 (epithelial marker), CTGF (profibrotic marker), and α-SMA (myofibroblast marker). The simultaneous presence (colocalization) of Ki-67 positive cells with α-SMA was determined using double immunofluorescence method. The percentage of reactive cells was analyzed by a Kruskal-Wallis test and the Dunn post hoc test. P<0.05 was considered statistically significant. The analysis revealed that the percentage of proliferating (Ki-67 positive) cells was highest in samples of patients with moderate dcSSc (3% in superficial and 4.6% in deeper parts of the gastric mucosa, which dropped to 1% in samples of patients with severe dcSSc). The percentage of α-smooth muscle actin (α-SMA) positive cells was 5% in control samples, 9% in superficial gastric mucosa of patients with lcSSc, while in the deeper layer it increased to 19% in samples of patients with moderate and 14% with severe dcSSc, indicating increased myofibroblast population and activity. Apoptotic cells positive on caspase-3 account for 1.5–2% in control samples, 8% in superficial, and 6% in deeper parts of the gastric mucosa of patients with moderate dcSSc. In samples of patients with severe dcSSc, apoptosis involved 50% of superficial epithelial and glandular cells and 30% of deeper glands, and correlated with increased CTGF expression and fibrosis, and decreased syndecan-1 expression. This data show that moderate dcSSc is the most proliferatively active form of SSc. Severe dcSSc is characterized by collagen deposition, surface epithelial defects, extensive apoptosis and decreased proliferation, atrophy and loss of function.