Once cancer unlocks, most organs grow a tumor on a timer. Leave it alive and it grows, spreads into other rooms, sends assassins after you and follows you into the next organ. Destroy it and you feast.
Cancer
Once cancer unlocks, most organs grow a tumor that grows, spreads and follows you deeper if left alive. Destroy one and your virus feasts.
Cancer unlocks for your whole save once any virus climbs far enough up its skill tree. Your next run introduces it with its own notice, and that organ is guaranteed a tumor.
The room where an organ's cancer grows, marked pink on the minimap. Its doors never lock, so you can walk away mid-fight and come back when you're ready.
While a tumor lives, a countdown in the corner shows when it will next grow or spread. It takes turns between the two, growing first, and ticks faster in deeper organs.
Every growth tick pushes the cancer up a stage: a tougher core, more satellite cells crowding the room, and quicker, faster-firing attacks. Deeper organs let tumors grow through more stages.
Instead of growing, a tick can spread the cancer. It takes over an unexplored fight room or buds a brand-new tumor room onto the map, and every spread is another tumor to destroy.
Walk out of a tumor fight and your progress is kept. Satellite cells you destroyed stay dead and the core keeps its damage, so you can retreat and finish the job later.
Cancer cells play by their own rules. They never become elites, never lose track of you once alerted, and never adapt into Cytokine Storm cells the way other cells can.
Eight cancers
Each organ grows its own real-world cancer with its own fight and weak point. The early organs share classic tumor parts; the deeper ones are fully unique.
A lumpy core ringed by satellite nodules that shield it and keep budding fast clone cells. Break the nodules first, and the exposed core goes down far more easily.
A growing core that keeps healing itself and launches metastasis seeds across the room. Any seed you don't shoot down takes root as a new nodule, making the core heal even faster.
A crowd of white blast cells that keep dividing. One gold leukemic stem cell hides among them, and killing it collapses the whole leukemia at once.
A germinal centre hidden in a crowd of identical lymphocytes. Most are harmless, but lymphoma clones lurk among them, and the core only turns soft while it swells to split.
A shell game: the core hides in one of several crypts, surfaces in another to fire, then dives again. Polyps along the walls drip caustic pools while you hunt it.
A liver tumor fed by satellite lobes through pulsing vessels. While any lobe lives it heals and shrugs off damage, so drop every lobe at once to trigger cirrhosis.
A malignant plasma cell drifting in slow circles, firing spirals of Y-shaped antibodies that lock on to you and punching bone lesions into the floor while its clones gather.
A brain tumor rooted among glial nodes. Tendrils creep across the floor at you while the core hops between nodes, so cut the nodes down to leave it stranded and exposed.
Know your enemy
Every piece of every tumor fight, from the core at its heart to the satellites it buds.
A lumpy, irregular mass of crusty nodules and tangled blood vessels. It never moves, hurts to touch and swells briefly before each attack. Destroy it and the whole tumor collapses.
A smaller, stationary lump around the core that keeps budding clone cells. In the Nasal Passage it shields the core; in the Lungs it speeds up the core's regrowth.
A small, misshapen cell with an oversized nucleus that rushes straight at you. One of the quickest cells in the fight but fragile, and ones budded mid-fight drop no nucleotides.
A dark cell the lung tumor launches toward a pulsing pink ring. It drifts slowly, so shoot it down before it lands and takes root as a new nodule.
A white cell almost filled by its nucleus. Blasts are fragile on their own, but they chase you down and keep dividing until the stem cell dies.
The gold-tinted, glowing cell that drives the leukemia. It keeps its distance, circles you and fires small volleys. Kill it and every blast dies with it.
An ordinary small lymphocyte drifting around the follicle. It never attacks and touching it does no harm, but it looks exactly like a lymphoma clone.
A cancer cell wearing a harmless lymphocyte's face. Get close or hit it and it shows its swollen, notched nucleus (CLONE!), fires a spread and hunts you down.
The lymphoma core: a lymph follicle gone wrong, with a dark mantle of packed cells around a pale, swollen centre. It resists damage except while swelling, then splits off new cells.
A tan, cauliflower-like adenocarcinoma riddled with malformed glands. It travels between crypts under the floor and can only be hurt during its brief time on the surface.
A dark well in the gut lining, ringed by goblet cells, where the colon tumor hides. It flashes as a warning just before the tumor bursts out of it.
A lumpy pink growth on a short stalk along the walls. It drips caustic pools toward you and keeps budding new polyps further along the wall.
A dark red-brown mass built of hexagonal lobules flecked with green bile. It heals and shrugs off damage while any lobe lives, and turns grey and cirrhotic when every lobe falls at once.
A smaller hexagonal nodule joined to the core by a pulsing vessel. It feeds the core, spits slow bile gobs at you and regrows from a bud after being destroyed.
A malignant plasma cell with an off-centre nucleus, stuffed with stored antibody and studded with Y-shaped M-proteins. It drifts in a slow circle, firing spirals and punching bone lesions.
A small oval plasma cell that keeps its distance, circling you and firing single Y-shaped antibodies. It's tougher than an ordinary clone cell, so don't ignore it.
A purple mass with a dark, dead heart and a rim of crowded cells, reaching out with infiltrating processes. It's untouchable while travelling under the floor and more vulnerable once every node is gone.
A slowly spinning, star-shaped tumor cell with long branching arms. Tendrils grow from it and the core hops between nodes. Destroyed nodes snap their tendrils back and stay dead.
Attacks
Every attack is telegraphed by a quick swell. Classic cores never fire the same volley pattern back to back; deeper organs add their own attacks and floor hazards.
A full ring of shots bursting out from the tumor in every direction at once. Bigger tumors fire denser, harder-hitting rings, so look for the gaps and slip through.
Twin arms of shots sweeping round in a spiral, turning clockwise or anticlockwise at random. Bigger tumors keep the spiral going longer, so read its direction early and move with it.
Quick spreads of shots fired straight at you in rapid bursts. They're the fastest shots of any shared pattern, and bigger tumors fire more bursts, so be ready to sidestep.
A ring of shots, then a second, faster ring offset into the gaps of the first. The follow-up comes quickly, so the safe lane you just found closes fast.
Streams of shots fired in a cross that turns as it fires. Bigger tumors keep it spinning for more waves, so circle with the rotation to stay in the gaps.
A wide, slow fan of large shots aimed at you. It's hard to slip through, and bigger tumors pack in more shots, so get out to the side early.
The lung tumor fires seeds at spots on the floor marked by pulsing pink rings. Any that land grow into new nodules, and it launches them faster with every stage.
Leukemic blasts keep splitting into new blasts until the crowd hits its limit. Thinning them only buys time; the real fix is killing the stem cell, which stops it all.
A pink ring rolls out from the germinal centre, and every hidden clone it passes briefly flickers its true face. It pulses more often as the tumor grows, so watch closely.
The germinal centre swells and flashes as a ring grows round it, then splits with a burst of shots and fresh cells. That swelling window is your moment to hit it hard.
The colon tumor bursts out of a flashing crypt behind a quick warning circle, hurting you if you're standing on top. Each time it dives, a decoy ripple heads to a different crypt.
Polyps lob a glob toward you that leaves a caustic pool on the floor. The pool fades after a short while but hurts as long as you stand in it.
Globs of bile lobbed at you and around you, each landing in a warned circle and leaving a bile puddle. The first one leads your movement, so don't run in a straight line.
A line of bile splashes sweeping out from the core toward you. Each splash lands where a circle warns first, so step out of the line before it reaches you.
Each satellite lobe spits a slow green gob of bile at you whenever you're in range. On their own they're easy to dodge, but several lobes add up quickly.
Bring every lobe down at the same time and the liver tumor's regeneration breaks. For a short while it can't heal and takes extra damage, then the lobes bud back one by one.
A spiral of Y-shaped antibodies that flare as a warning, then all turn at once toward where you're standing. They fly to where you were, not where you're going, so keep moving.
Marked circles at and around you collapse into punched-out holes in the bone. The first lands right on you, and each hole keeps hurting for a while if you stand in it.
Myeloma clones circle at range and fire single Y-shaped antibodies at you. Each shot is light on its own, but a few clones firing together can pin you down.
Tendrils creep slowly across the floor toward you, hold briefly, then pull back, and touching one hurts. They grow from the nearest nodes and snap back fast when their node is destroyed.
The core marks a spot by a node with a purple ring, shrinks, slips under the floor and travels there. It can't be hurt in transit, and with no nodes left it's stuck.
As it surfaces, the glioblastoma fires rings of shots back to back, each with a gap to slip through on opposite sides. Find the first gap, then cross for the next.
Metastasis
Leave an organ with a tumor still alive and the cancer follows you into the next one, still growing and sending assassins after you.
Leave an organ with a living tumor and the cancer comes with you, arriving in the next organ at the stage it reached. The leave prompt warns you before you go.
Sometimes after a metastasis, the host fights back with radiation. The tumor shrinks a stage, but it scorches you too, cutting your health and leaving you with radiation sickness for a while.
Cancer assassins
A metastasized cancer sends squads of assassin cells after you. Each organ's cancer sends its own kind with a twist, and every squad is bigger than the last.
A red heartbeat warning, then a squad of nearly invisible cells arrives at the far entrance. They stalk you, mark a red line and pounce, and each bite leaves you taking extra damage.
A dart of layered keratin scales, the Nasal Passage cancer's assassin. It's the standard model: it stalks you nearly invisible, marks a line and pounces.
A lacy cell gliding on thin membrane wings. Its pounce glides further than any other assassin's, down a longer marked line, so backing away won't save you.
A blast cell bristling with needle-like Auer rods, and the fastest assassin of all. It closes the distance quicker than any other assassin, so react early.
Instead of cloaking, it disguises itself as an ordinary blue lymphocyte. Up close or when it strikes, it reveals its owl-eyed twin nuclei and pounces.
A cell whose nucleus is squashed to the rim by mucus. It's almost completely invisible at range, though a little slower than the other assassins.
A hexagonal cell threaded with green bile. Leave it alone for a moment and it starts healing itself, so once you start hitting it, don't stop.
A jagged bone shard. Wherever its pounce lands, it punches a small bone lesion into the floor that hurts to stand in for a short while.
A narrow cell trailing long, wavy processes. After its first pounce it re-aims and pounces again almost straight away, down a brand-new marked line.
The feast
Rapidly dividing cells are a feast for a virus. Destroy the core and the whole tumor collapses at once, and the bigger it grew, the bigger the payout.
TUMOR DESTROYED: every cell of the tumor dies with the core and a pile of loot drops. Deeper organs and bigger tumors pay more, and its hazards vanish from the floor.
Satellite parts pay a few nucleotides as you destroy them, so a tumor fight rewards you along the way. The core itself pays only when the whole tumor collapses.
Your first tumor challenge: destroy a single tumor. It's the opening step of the tumor challenge ladder and a gentle nudge to take on your first cancer.
The middle step of the tumor challenge ladder. Once you've got the hang of tumor fights, destroy a handful of them to complete it.
The top step of the tumor challenge ladder, for dedicated cancer hunters. Destroy a large number of tumors to finish the ladder and prove your virus is truly oncolytic.
A daily challenge that asks for just one thing: find a tumor today and destroy it. A simple goal that fits into any run once cancer is unlocked.
A weekly challenge: destroy a few tumors before the week is out. There's no rush, so you can chip away at it across several runs.
Exploration challenges can ask you to discover tumor rooms, either one or several. Keep an eye on the minimap for pink rooms as you explore each organ.
Oncolytic virus
Real oncolytic viruses are engineered to burst cancer cells. In Pathogen, traits, modifiers, hosts and a city policy make tumors weaker, richer, faster or more common.
A Cancer trait from mutation orbs that makes you hit tumors and all their cells harder, assassins included. Rarer versions hit harder still, and picking it again stacks.
A run modifier crafted between runs. Tumors take far more damage and pay out far more, but the catch is that every organ grows a tumor.
A run modifier crafted between runs for bigger rewards. Tumors pay out much more, but they grow much faster and start a stage bigger, so you have less time to react.
Load Oncolytic Strain and Carcinogen Exposure together and every tumor you destroy heals you fully. A great reason to go hunting cancers with both modifiers on.
Stack Oncolytic Strain, Carcinogen Exposure and Nutrient Cache together and tumors pay out even more, while destroying one heals you fully. A rich reward for loading all of them.
The host is riddled with cancer. Every organ grows a tumor that starts a stage bigger, grows faster and spreads further, but tumors pay out much more and so does the whole run.
The host is on chemotherapy. The drugs weaken immune cells and make tumors easier to destroy, but they poison you too, lowering your max health.
A helpful host gene: p53, the guardian of the genome, slows tumor growth. The rarer the host, the stronger the effect, giving you more time to deal with each cancer.
A harmful host gene found only in people. Cells can't repair their DNA, so cancers grow faster and spread further, and rarer hosts make it worse.
Take Mexico City in Pandemic Game Mode and this policy puts a tumor in every organ. They grow faster than usual, but each one pays out far more.
While CRISPR is active, ordinary tumor cells you touch are cut apart instantly. Tumor cores and the leukemic stem cell resist being cut, but still take heavy damage with every touch.
Next up
Procedural organs, traits that stack into chaos, power-ups, synergies and secrets.
