Close temporal relationship between onset of cancer and scleroderma in patients with RNA polymerase I/III antibodies

Abstract

Objective: This study was undertaken to examine the temporal relationship between scleroderma development and malignancy, and to evaluate whether this differs by autoantibody status among affected patients.

Methods: Study participants had a diagnosis of scleroderma, a diagnosis of cancer, cancer, an available serum sample, and a cancer pathology specimen. Sera were tested for autoantibodies against topoisomerase I, centromere, and RNA polymerase I/III by immunoprecipitation and/or enzyme-linked immunosorbent assay. Clinical and demographic characteristics were compared across autoantibody categories. Expression of RNA polymerases I and III was evaluated by immunohistochemistry using cancerous tissue from patients with anti-RNA polymerase antibodies.

Results: Twenty-three patients were enrolled. Six patients tested positive for anti-RNA polymerase I/III, 5 for anti-topoisomerase I, and 8 for anticentromere, and 4 were not positive for any of these antigens. The median duration of scleroderma at cancer diagnosis differed significantly between groups (-1.2 years in the anti-RNA polymerase I/III group, +13.4 years in the anti-topoisomerase I group, +11.1 years in the anticentromere group, and +2.3 years in the group that was negative for all antigens tested) (P = 0.027). RNA polymerase III demonstrated a robust nucleolar staining pattern in 4 of 5 available tumors from patients with antibodies to RNA polymerase I/III. In contrast, nucleolar RNA polymerase III staining was not detected in any of 4 examined tumors from the RNA polymerase antibody-negative group (P = 0.048).

Conclusion: Our findings indicate that there is a close temporal relationship between the onset of cancer and scleroderma in patients with antibodies to RNA polymerase I/III, which is distinct from scleroderma patients with other autoantibody specificities. In this study, autoantibody response and tumor antigen expression are associated. We propose that malignancy may initiate the scleroderma-specific immune response and drive disease in a subset of scleroderma patients.

Figure 1. Distribution of Scleroderma Duration at Cancer Diagnosis by Autoantibody Status

There is a tight temporal relationship between malignancy diagnosis and scleroderma onset in patients producing anti-RNA polymerase I/III antibodies (Anti-RNA pol I/III) compared to patients with anti-topoisomerase I antibodies (Anti-topo) and patients with antibodies to centromere (Anti-centromere). The antibody negative group (Negative) has a similar close relationship between scleroderma and cancer onset.

Figure 2. RNA polymerase I staining is prominent in cancerous ovary and breast tissue from scleroderma patients compared to normal ovary and breast. Paraffin sections from cancerous ovary (panels A and B) and breast (panels E and F) from scleroderma patients with cancer, as well as normal ovary (panels C and D) and normal breast (panels G and H) were stained with antibodies against RNA polymerase I as described in the methods section

In all panels, the brown color represents RNA polymerase I staining, with nuclei in blue (Mayers’ hematoxylin counterstain). Magnifications are 10× (upper panels of each set - panels A, C, E and G) and 40× (lower panels of each set - panels B, D, F and H). In each set, the 40× panel is a magnification of part of the field shown at10×. The cancer sections shown were from subjects # 4 (ovarian cancer) and # 42 (breast cancer).

Figure 3. RNA polymerase III staining is prominent in cancerous ovary and breast tissue from scleroderma patients compared to normal ovary and breast. Paraffin sections from cancerous ovary (panels A and B) and breast (panels E and F) from scleroderma patients with cancer, as well as normal ovary (panels C and D) and normal breast (panels G and H) were stained with antibodies against RNA polymerase III as described in the methods section

In all panels, the brown color represents RNA polymerase III staining, with nuclei in blue (Mayers’ hematoxylin counterstain). Magnifications are 10× (upper panels of each set - panels A, C, E and G) and 40× (lower panels of each set - panels B, D, F and H). In each set, the 40× panel is a magnification of part of the field shown at10×. The cancer sections shown were from subjects # 4 (ovarian cancer) and # 42 (breast cancer).