Prognostic significance of in situ carcinoma associated with invasive breast carcinoma. A natural experiment in cancer immunology?

Background: Our previous studies indicate that the in situ phase of mammary carcinogenesis is characteristically associated with cell-mediated immunity (CMI against an immunogen shared by most breast carcinomas. Such reactivity is inversely correlated with stage and appears to impede in situ-to-invasive progression and lethality from invasive breast carcinoma. If in situ carcinomas are indeed associated with ambient, prognostically favorable immunity against such an immunogen, one would expect lethality from invasive breast carcinoma to be reduced in patients with a diagnosis of a prior, simultaneous, or subsequent in situ breast carcinoma.