Based on review of the most variable cases, increased sTIL density at the leading edge versus central tumor were contributing factors in 43%, 17% and 54% of cases in ring studies 1 through 3, respectively (Fig. 4a); and marked heterogeneity of sTIL density within the tumor was identified in 29% cases in ring study 1 only (Fig. 4b). The gene discussed is STIL; the disease is neoplasm.